Federal Register / Vol. 66, No. 10 / Tuesday, January 16, 2001 / Proposed Rules 3523

add comments and then send it to the

Manager, Seattle ACO.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

Special Flight Permit

(d) Special flight permits may be issued per

sections 21.197 and 21.199 of the Federal

Aviation Regulations (14 CFR 21.197 and

21.199) to operate the airplane to a location

where the requirements of this AD can be

accomplished.

Issued in Renton, Washington, on January

9, 2001.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 01–1235 Filed 1–12–01; 8:45 am]

BILLING CODE 4910–13–P

DEPARTMENT OF HEALTH AND

HUMAN SERVICES

Food and Drug Administration

21 CFR Parts 16 and 807

[Docket No. 00N–1625]

Medical Devices; Rescission of

Substantially Equivalent Decisions and

Rescission Appeal Procedures

AGENCY: Food and Drug Administration,

HHS.

ACTION: Proposed rule.

SUMMARY: The Food and Drug

Administration (FDA) is proposing

regulations under which FDA may

rescind a decision issued under the

Federal Food, Drug, and Cosmetic Act

(the act) that a device is substantially

equivalent to a legally marketed device,

and, therefore, may be marketed. In

addition, under this proposal, a

premarket notification (commonly

known as a ‘‘510(k)’’) holder may

request administrative review of a

proposed rescission action. This

proposed rule is being issued in order

to standardize the procedures for

considering rescissions.

DATES: Submit written comments by

April 16, 2001.

ADDRESSES: Submit written comments

to the Dockets Management Branch

(HFA–305), Food and Drug

Administration, rm. 1061, 5630 Fishers

Lane, Rockville, MD 20852.

FOR FURTHER INFORMATION CONTACT:

Heather S. Rosecrans, Center for Devices

and Radiological Health (HFZ–404),

Food and Drug Administration, 9200

Corporate Blvd., Rockville, MD 20850,

301–594–1190.

SUPPLEMENTARY INFORMATION:

I. Background

The Medical Device Amendments

(Public Law 94–295) (the amendments)

to the act (21 U.S.C. 301 et seq.) were

enacted on May 28, 1976. Among other

things, the amendments directed FDA to

issue regulations classifying all medical

devices into one of three regulatory

control categories. The classification

depends upon the degree of regulation

necessary to provide reasonable

assurance of the safety and effectiveness

of the device.

Under section 513(a)(1)(A) of the act

(21 U.S.C. 360c(a)(1)(A)), class I devices

are subject to a comprehensive set of

regulatory provisions applicable to all

classes of devices, e.g., registration and

listing, prohibitions against adulteration

and misbranding, and good

manufacturing practice requirements. A

class I device is exempt from the

premarket notification requirements of

the act unless it is intended for a use

which is of substantial importance in

preventing impairment of human

health, or the device presents a potential

unreasonable risk of illness or injury

under section 510(l) of the act (21 U.S.C.

360(l)). Class II devices are subject to

special controls as well as general

controls. These special controls may

consist of performance standards,

postmarket surveillance, patient

registries, FDA guidelines, or other

appropriate controls under section

513(a)(1)(B) of the act. Class III devices

require premarket approval (PMA) or a

completed product development

protocol by FDA before they may be

marketed, unless they are class III

devices for which we have not called for

PMA’s under section 515(b) of the act

(21 U.S.C. 360e(b)).

II. Premarket Notification

Requirements

Section 510(k) of the act requires each

person who is required to register and

who proposes to begin the introduction

or delivery for introduction into

interstate commerce for commercial

distribution of a device intended for

human use to submit a 510(k).

Throughout this proposal, we use the

following terms:

1. The ‘‘510(k) submitter.’’—the

person who submitted the 510(k) to the

FDA.

2. The ‘‘510(k) holder’’—the person

who possesses the rights to market the

device that is the subject of a 510(k)

substantial equivalence order. (The

510(k) submitter and the 510(k) holder

may or may not be the same person.)

3. The ‘‘510(k) holder of record’’—the

person whom FDA has on file as being

the 510(k) holder.

The proposed rule adds these

definitions to 21 CFR 807.3.

There may be instances when 510(k)

ownership has changed without FDA’s

knowledge. In the event of a proposed

rescission, FDA would provide notice to

the 510(k) holder of record. FDA would

attempt to notify the holder of record by

registered letter. FDA would also post

notice of a proposed rescission on

FDA’s Center for Devices and

Radiological Health’s (CDRH) home

page on the Internet at http://

www.fda.gov/cdrh/index.html. To

protect the privacy of the 510(k) holder,

only the proposed rescission would be

listed; the factual basis and reasons for

the rescission would not be posted on

CDRH’s home page on the Internet.

Under the 510(k) process, the 510(k)

submitter may claim that its new device

is substantially equivalent to a legally

marketed class I or class II device or to

a preamendments class III device that is

not yet required to be the subject of an

approved premarket approval

application. If, after reviewing the

510(k), the agency determines that the

device is substantially equivalent to the

legally marketed device (as defined in

21 CFR 807.92(a)(3)), the agency will

issue an order permitting the 510(k)

submitter to market its device without

the need for the more rigorous

premarket approval under section 515 of

the act.

The criteria the agency must use to

determine substantial equivalence are in

section 513(i) of the act. Section 513(i)

of the act defines substantial

equivalence to mean that the device has

the same intended use as the predicate

device and that FDA, by order, has

found that the device—(i) has the same

technological characteristics as the

predicate device, or (ii)—(I) has

different technological characteristics

and the information submitted that the

device is substantially equivalent to the

predicate device contains information,

including clinical data if deemed

necessary by FDA, that the device is as

safe and effective as a legally marketed

device, and (II) does not raise different

questions of safety and effectiveness

than the legally marketed device.

The statute allows 510(k) marketing

clearance only for devices that FDA

determines are comparable in safety and

effectiveness to a legally marketed

device. New devices that are not

substantially equivalent must remain in

class III and meet the premarket

approval requirements under section

515 of the act before they can be

marketed, unless the device is

reclassified under section 513(f) of the

act.

3524 Federal Register / Vol. 66, No. 10 / Tuesday, January 16, 2001 / Proposed Rules

III. Authority to Rescind

On October 25, 1994, the Health

Industry Manufacturers Association

(HIMA) submitted a petition [Docket

No. 94A–0388] to FDA in which they

requested that FDA issue an advisory

opinion stating that the act does not

provide authority for FDA to withdraw

a premarket notification (510(k)) order.

In the alternative, HIMA requested that,

if FDA determined that it did have the

authority to withdraw a premarket

notification order, FDA should: (1)

Refrain from rescinding such a decision

without establishing procedures

assuring the 510(k) holder due process

rights; (2) provide the 510(k) holder an

opportunity for an informal hearing

under section 201(x) (formerly 201(y)) of

the act (21 U.S.C. 321(x)) before issuing

a rescission order; and (3) issue a

regulation providing the 510(k) holder

with the opportunity to request a

hearing to challenge a proposed

withdrawal.

On September 11, 1995, FDA issued

an interim response to the HIMA

petition. In this interim response, FDA

said that it intended to issue a proposed

rule specifying the authority for

rescinding a substantial equivalence

decision as well as the grounds under

which such decisions can be made. The

interim response also stated that,

pending the completion of this

rulemaking process, FDA would only

rescind, or propose to rescind,

substantial equivalence orders in cases

involving: (1) A serious adverse risk to

public health or safety, (2) data integrity

or fraud, or (3) other compelling

circumstances. On September 22, 1997,

FDA issued a final response to the

petition that restated the policy

established in the interim response.

Although the act does not expressly

address rescission of substantial

equivalence orders, section 513(f) and

(i) of the act indicate that rescission is

consistent with FDA’s authority under

the act to allow marketing of a device

under the 510(k) process only if the

device is substantially equivalent to a

legally marketed device.

FDA has authority under its

administrative procedure regulations to

reconsider the issuance of substantial

equivalence orders § 10.33(a) and (h) (21

CFR 10.33(a) and (h)). Section 10.33(a)

states the ‘‘Commissioner may at any

time reconsider a matter, on the

Commissioner’s own initiative or on the

petition of an interested person.’’

Section 10.33(h) states the

‘‘Commissioner may initiate the

reconsideration of all or part of a matter

at any time after it has been decided or

action has been taken.’’ Both § 10.33(a)

and (h) provide the agency with

authority to reconsider and rescind an

order determining a device to be

substantially equivalent.

Section 10.75 (21 CFR 10.75) also

provides the agency with authority for

supervisory review of decisions made

by an employee other than the

Commissioner of Food and Drugs (the

Commissioner). This internal review

can be undertaken to resolve agency

disputes, review policy and unusual

situations affecting public interest, or as

required by delegations of authority.

Section 10.75 supports the agency’s

authority to correct the decisions that it

determines were made in error by

employees other than the

Commissioner.

Case law also supports FDA’s

authority to correct inappropriate

decisions even in the absence of explicit

statutory or regulatory authority. In

American Therapeutics Inc. v. Sullivan,

755 F. Supp. 1, 2 (D.D.C. 1990), FDA

rescinded a drug approval that had been

issued by mistake. The court held that,

although there were no regulations or

statutory provisions that expressly

contemplated rescission of an approval

by mistake, the agency must be given

latitude to correct mistakes.

The Supreme Court has also

recognized an implied authority in

agencies to reconsider and rectify errors,

even if the applicable statute and

regulations do not expressly provide for

such reconsideration. For example, in

concluding that the Interstate Commerce

Commission could order a refund to

correct a prior error, the Supreme Court

stated that ‘‘[a]n agency, like a court,

can undo what is wrongfully done by

virtue of its order.’’ United Gas

Improvement Co. v. Callery Properties,

Inc., 382 U.S. 223, 229 (1965). See also

American Trucking Association v.

Frisco Trans., 358 U.S. 133, 145 (1958)

(‘‘the presence of authority in

administrative officers and tribunals to

correct [inadvertent ministerial] errors

has long been recognized—probably so

well recognized that little discussion

has ensued in the reported cases.’’);

Copley v. Elliot, 948 F. Supp. 586, 589

(W.D. Va. 1996) (‘‘[i]t is generally

always within the power of a

government agency to correct its

mistakes.’’).

Other courts have similarly

recognized this implied authority, Iowa

Power and Light Co. v. United States,

712 F.2d 1292, 1294–97 (8th Cir. 1983)

(ICC could retroactively impose higher

tariff to correct legal error), cert. denied,

466 U.S. 949 (1984); Bookman v. United

States, 453 F.2d 1263, 1265 (Ct. Cl.

1972) allowing agency to reconsider

decisions in absence of statutory or

regulatory authorization after noting

general rule that ‘‘[e]very tribunal,

judicial or administrative, has some

power to correct its own errors or

otherwise appropriately to modify its

judgment, decree, or order’’) (quoting 2

K. Davis, Administrative Law Treatise,

section 18.09 (1958)).

Moreover, some courts have held that

FDA has a duty to correct errors if it

learns its prior position was incorrect.

See United States v. 60 28-Capsule

Bottles,. 211 F. Supp. 207, 215 (D. N.J.

1962) (FDA has a duty to change its

position with reference to the efficacy of

a drug if it subsequently learns that its

original position was in error); see also

Bentex Pharmaceuticals Inc. v.

Richardson, 463 F.2d. 363, 368 n. 17

(4th Cir. 1972) rev’d Weinberger v.

Bentex Pharmaceuticals, Inc., 412 U.S.

645 (1979) (noting FDA not estopped

from alleging product was a ‘‘new

drug,’’ even though the agency had

given the opinion that similar drugs

were not ‘‘new drugs’’).

IV. Bases for Proposing Rescission of a

510(k) Substantial Equivalence

Decision

FDA examines a vast array of device

technologies each year under the

premarket notification (510(k)) process.

Under the 510(k) process, each

submitter has the burden of

demonstrating that its device is at least

as safe and effective as a legally

marketed device. If FDA discovers that

a premarket notification submission

does not meet the criteria of substantial

equivalence and the submission was

cleared in error, FDA will issue a

registered letter to the 510(k) holder of

record proposing to rescind the order of

substantial equivalence. FDA will also

post notice of the proposed rescission

on CDRH’s home page on the Internet.

Under proposed § 807.103, FDA may

propose rescission of a substantial

equivalence decision if one or more of

the following criteria are met. FDA

believes that, if any one of these criteria

is met, there is no longer reasonable

assurance that the device is at least as

safe and effective as a legally marketed

device.

1. The premarket notification does not

satisfy the criteria under § 807.100(b)(1)

or (b)(2) for a determination of

substantial equivalence.

2. Based on new safety or

effectiveness information, the device is

not substantially equivalent to a legally

marketed device.

3. (i) FDA or the 510(k) holder has

removed from the market, for safety and

effectiveness reasons, one or more

legally marketed device(s) on which the

substantial equivalence determination

Federal Register / Vol. 66, No. 10 / Tuesday, January 16, 2001 / Proposed Rules 3525

was based, or (ii) a court has issued a

judicial order determining the legally

marketed device(s), on which the

substantial equivalence determination

was based, to be misbranded or

adulterated.

4. The premarket notification

contained or was accompanied by an

untrue statement of material fact.

5. The premarket notification

included or should have included

information about clinical studies and

these clinical studies failed to comply

with applicable Institutional Review

Board regulations (21 CFR part 56) or

informed consent regulations (21 CFR

part 50) in a way that the rights or safety

of human subjects were not adequately

protected.

6. The premarket notification

contained clinical data submitted by a

clinical investigator who has been

disqualified under 21 CFR 812.119.

These would be bases to rescind

because information in the 510(k) is

incorrect, incomplete, unreliable, or not

evaluated properly by FDA in

accordance with section 513(f) and (i) of

the act.

V. Procedures for Rescinding a 510(k)

Substantial Equivalence Order

Before issuing an order rescinding a

510(k) substantial equivalence decision,

FDA would notify the 510(k) holder of

record of its intent to rescind by

registered mail. This notice would state

the facts upon which the action is based

and would notify the 510(k) holder of

record of an opportunity for a hearing

under part 16 (21 CFR part 16). The

notice would include the time within

which a hearing may be requested and

the name, address, and telephone

number of the FDA employee to whom

any request for a hearing is to be

addressed. FDA would also post notice

of a proposed rescission on CDRH’s

home page on the internet. The Internet

site will only state that a rescission of

the 510(k) is proposed and information

about the hearing and will not state the

facts upon which the action is based.

Because FDA may be unaware that

ownership of a 510(k) has changed, the

notification by Internet site would serve

as an additional means of assuring that

the current 510(k) holder has notice.

If FDA believes that immediate action

to remove a dangerous device from the

market is necessary to protect the public

health, the agency may, in accordance

with §§ 16.24(d), 16.60(h) and 10.19,

waive, suspend, or modify any part 16

procedure or procedures stated in part

807. Ordinarily, the amount of time

specified in the notice for requesting a

hearing will be not less than 3 working

days. FDA ordinarily would provide

notice by registered mail. Under

circumstances presenting the need for

immediate action, FDA may, for

example, attempt to contact the 510(k)

holder by telephone instead of

registered mail.

If a 510(k) holder fails to request a

hearing within the timeframe specified

by FDA in the notice of opportunity for

hearing, FDA will consider the failure to

request a hearing a waiver of such

hearing and FDA will issue a letter

rescinding the order determining

substantial equivalence.

If, after a part 16 hearing is held, the

agency decides to proceed with the

rescission of an order determining

substantial equivalence, FDA will issue

to the 510(k) holder of record an order

rescinding the order determining

substantial equivalence. The rescission

order will state each ground for

rescinding the substantial equivalence

determination. FDA will give the public

notice of an order rescinding a

determination of substantial

equivalence. The notice will be placed

on CDRH’s home page on the Internet.

VI. Environmental Impact

The agency has determined under 21

CFR 25.30(h) that this action is of a type

that does not individually or

cumulatively have a significant effect on

the human environment. Therefore,

neither an environmental assessment

nor an environmental impact statement

is required.

VII. Analysis of Impacts

FDA has examined the impacts of the

proposed rule under Executive Order

12866, the Regulatory Flexibility Act (5

U.S.C. 601–612) (as amended by subtitle

D of the Small Business Regulatory

Fairness Act of 1996 (Public Law 104–

121)), and the Unfunded Mandates

Reform Act of 1995 (Public Law 104–4)).

Executive Order 12866 directs agencies

to assess all costs and benefits of

available regulatory alternatives and,

when regulation is necessary, to select

regulatory approaches that maximize

net benefits (including potential

economic, environmental, public health

and safety, and other advantages;

distributive impacts; and equity). The

agency believes that this proposed rule

is consistent with the regulatory

philosophy and principles identified in

the Executive order.

The Regulatory Flexibility Act

requires agencies to analyze regulatory

options that would minimize any

significant impact of a rule on small

entities, if a rule would have a

significant economic impact on a

substantial number of small entities.

The proposed rule will not have a

significant economic impact on a

substantial number of small entities.

FDA has only proposed five rescissions

from 1997 through 1999 and one

rescission through May 2000. FDA does

not believe that this level of activity

represents a significant impact on a

substantial number of small entities. In

addition, the rule will be applied only

when the criteria for rescission are met.

The agency therefore certifies that this

rule, if finalized, will not have a

significant economic impact on a

substantial number of small entities.

Section 202(a) of the Unfunded

Mandates Reform Act of 1995 requires

that agencies prepare a written

statement of anticipated costs and

benefits before proposing any rule that

may result in an expenditure by State,

local, and tribal governments, in the

aggregate, or by the private sector, of

$100 million in any one year (adjusted

annually for inflation). The Unfunded

Mandates Reform Act does not require

FDA to prepare a statement of costs and

benefits for the proposed rule, because

the proposed rule is not expected to

result in any 1-year expenditure that

would exceed $100 million adjusted for

inflation.

VIII. Request for Comments

Interested persons may submit to the

Dockets Management Branch (address

above) written comments regarding this

proposal by April 16, 2001. Two copies

of any comments are to be submitted,

except that individuals may submit one

copy. Comments are to be identified

with the docket number found in

brackets in the heading of this

document. Received comments may be

seen in the Dockets Management Branch

between 9 a.m. and 4 p.m. Monday

through Friday.

IX. Paperwork Reduction Act of 1995

FDA has tentatively determined that

this proposed rule contains no

collections of information. Therefore,

clearance from the Office of

Management and Budget under the

Paperwork Reduction Act of 1995 is not

required.

List of Subjects

21 CFR Part 16

Administrative practice and

procedure.

21 CFR Part 807

Confidential business information,

Imports, Medical devices, Reporting and

recordkeeping requirements.

Therefore, under the Federal Food,

Drug, and Cosmetic Act and under the

authority delegated to the Commissioner

3526 Federal Register / Vol. 66, No. 10 / Tuesday, January 16, 2001 / Proposed Rules

of Food and Drugs, it is proposed that

21 CFR parts 16 and 807 be amended as

follows:

PART 16—REGULATORY HEARING

BEFORE THE FOOD AND DRUG

ADMINISTRATION

1. The authority citation for 21 CFR

part 16 continues to read as follows:

Authority: 15 U.S.C. 1451–1461; 21 U.S.C.

141–149, 321–394, 467f, 679, 821, 1034; 28

U.S.C. 2112; 42 U.S.C. 201–262, 263b, 364.

2. Section 16.1 is amended in

paragraph (b)(2) by numerically adding

an entry for § 807.103 to read as follows:

§ 16.1 Scope.

* * * * *

(b) * * *

(2) * * *

§ 807.103 relating to rescission of

substantially equivalent orders and

rescission appeal procedures.

* * * * *

PART 807—ESTABLISHMENT

REGISTRATION AND DEVICE LISTING

FOR MANUFACTURERS AND INITIAL

IMPORTERS OF DEVICES

3. The authority citation for 21 CFR

part 807 continues to read as follows:

Authority: 21 U.S.C. 331, 351, 352, 360,

360c, 360e, 360i, 360j, 371, 374.

4. Section 807.3 is amended by

adding new paragraphs (t), (u), and (v)

to read as follows:

§ 807.3 Definitions.

* * * * *

(t) 510(k) submitter means the person

who submitted the 510(k) to FDA.

(u) 510(k) holder means the person

who possesses the rights to market a

device that is the subject of 510(k)

substantial equivalence order.

(v) 510(k) holder of record means the

person FDA has on file as being the

holder of the 510(k).

5. Section 807.103 is added to subpart

E to read as follows:

§ 807.103 Rescission of 510(k)

substantially equivalent orders and

rescission appeal procedures.

(a) Grounds for rescinding a

substantially equivalent order. FDA may

issue an order rescinding a

determination of substantial

equivalence under this section, if FDA

determines that any one of the following

grounds exist:

(1) The premarket notification does

not satisfy the criteria under

§ 807.100(b)(1) or (b)(2) for a

determination of substantial

equivalence.

(2) Based on new safety or

effectiveness information, the device is

not substantially equivalent to a legally

marketed device.

(3) (i) FDA or the 510(k) holder has

removed from the market, for safety and

effectiveness reasons, one or more

legally marketed device(s) on which the

substantial equivalence determination

was based, or

(ii) A court has issued a judicial order

determining the legally marketed

device(s) on which the substantial

equivalence determination was based to

be misbranded or adulterated.

(4) The premarket notification

contained or was accompanied by an

untrue statement of material fact.

(5) The premarket notification

included or should have included

information about clinical studies and

these clinical studies failed to comply

with applicable institutional review

board regulations (part 56 of this

chapter) or informed consent

regulations (part 50 of this chapter) in

a way that the rights or safety of human

subjects were not adequately protected.

(6) The premarket notification

contained clinical data submitted by a

clinical investigator who has been

disqualified under § 812.119 of this

chapter.

(b) Notice of proposed rescission and

opportunity for a hearing. Before issuing

an order rescinding a substantial

equivalence order, FDA will issue the

510(k) holder of record a notice of the

agency’s intent to rescind the 510(k) by

registered letter, together with a notice

of an opportunity for an informal

hearing under part 16 of this chapter.

FDA will also post notice of a proposed

rescission on the FDA’s Center for

Devices and Radiological Health’s

(CDRH) home page on the Internet at

http://www.fda.gov/cdrh/index.html. If

FDA believes that immediate action to

remove a dangerous device from the

market is necessary to protect the public

health, the agency may, in accordance

with §§ 16.24(d), 16.60(h), and 10.19 of

this chapter, waive, suspend, or modify

any part 16 procedure and, in

accordance with this section, waive,

suspend, or modify any part 807

procedure.

(c) Failure to request a hearing. If a

510(k) holder fails to request a hearing

within the timeframe specified by FDA

in the notice of opportunity for hearing,

FDA will consider the failure to request

a hearing a waiver of such hearing and

FDA will issue a letter rescinding the

order determining substantial

equivalence.

(d) Rescission order. If the 510(k)

holder does not request a hearing or if,

after proceedings in accordance with

this part and part 16 of this chapter are

completed, the agency decides to

proceed with the rescission of an order

determining substantial equivalence,

FDA will issue to the 510(k) holder of

record an order rescinding the order

determining substantial equivalence.

The rescission order will state each

ground for rescinding the substantial

equivalence determination.

(e) Public notice of final action. FDA

will give the public notice of the order

rescinding a determination of

substantial equivalence. If FDA

determines not to finalize a proposed

rescission, FDA will also give the public

notice of this determination. These

notices will be placed on FDA’s home

page on the Internet.

Dated: January 5, 2001.

Ann M. Witt,

Acting Associate Commissioner for Policy.

[FR Doc. 01–1128 Filed 1–12–01; 8:45 am]

BILLING CODE 4160–01–F

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 136, 141, and 143

[FRL–6918–1]

RIN 2040–AD59

Guidelines Establishing Test

Procedures for the Analysis of

Pollutants Under the Clean Water Act;

National Primary Drinking Water

Regulations; and National Secondary

Drinking Water Regulations; Methods

Update

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Proposed rule.

SUMMARY: EPA is proposing action on a

methods update rule that approves

revised versions of test procedures (i.e.,

analytical methods) for the

determination of chemical, radiological,

and microbiological pollutants and

contaminants in wastewater and

drinking water. The revisions concern

methods published by one or more of

the following organizations: American

Society for Testing Materials (ASTM),

United States Geological Survey

(USGS), United States Department of

Energy (DOE), American Public Health

Association (APHA), American Water

Works Association (AWWA), and Water

Environment Federation (WEF).

Previously approved versions of the

methods remain approved. This rule

will give the analytical community a

larger selection of analytical methods.

Today’s action also corrects

typographical errors and updates

references where appropriate.