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                               THE STATE OF TEXAS
                               SECRETARY OF STATE

     IT IS HEREBY  CERTIFIED that the attached is/are true and correct copies of
the following described document(s) on file in this office:

                              OCCUCENTERS I, L.P.
                                 FILE #93240-10

CERTIFICATE OF LIMITED PARTNERSHIP                             NOVEMBER 15, 1996
ASSUMED NAME CERTIFICATE                                        OCTOBER 19, 1998

                                   IN TESTIMONY  WHEREOF, I HAVE HEREUNTO SIGNED
                                   MY NAME OFFICIALLY AND CAUSED TO BE IMPRESSED
                                   HEREON  THE SEAL OF STATE AT MY OFFICE IN THE
                                   CITY OF AUSTIN, ON AUGUST 9, 1999.


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                                                       /s/ Elton Bomer
                                             -----------------------------------
                                                         ELTON BOMER          PH
                                                      SECRETARY OF STATE

<PAGE>

                       CERTIFICATE OF LIMITED PARTNERSHIP

                                                  ------------------------------
                                                               FILED
                                                        In the Office of the
                                                   Secretary of State of Texas
                                                           Nov 15 1996

                                                       Corporations Section
                                                  ------------------------------


1. The name of the limited partnership is: OccuCenters I, L.P.

2. The address of the registered office is 360 N. St. Paul Street, Dallas, Texas
   75201.

3. The name of the registered agent at the above address is CT. Corporation
   System.

4. The address where the records of the limited partnership are to be kept or
   made available (pursuant to TRLPA art. 6132a-1,  sec. 1.07) is 3010 LBJ
   Freeway, Suite 400. Dallas, Tx 75234.

5. The name, mailing address and street address of the business or residence of
   each general partner is as follows:

          GENERAL PARTNER                MAILING/BUSINESS ADDRESS
          ---------------                ------------------------

          OccuCenters, Inc.              3010 LBJ Freeway, Suite 400
                                         Dallas, TX 75234


                                         OCCUCENTERS, INC.

                                         By: /s/ Richard A. Parr II
                                             ---------------------------------
                                         Richard A. Parr II, Executive
                                         Vice President and General Counsel

<PAGE>

                            ASSUMED NAME CERTIFICATE

                                                 ------------------------------
                                                               FILED
                                                        In the Office of the
                                                   Secretary of State of Texas
                                                           Oct 19 1998

                                                       Corporations Section
                                                  ------------------------------


1. The name of the corporation limited liability company, limited partnership or
   registered  limited  liability  partnership  as  stated  in its  articles  of
   incorporation, articles of organization,  certificate of limited partnership,
   application or comparable document is OccuCenters I, L.P.
                                         ---------------------------------------

   -----------------------------------------------------------------------------

2. The assumed name under which the business or professional service is or is to
   be conducted or rendered is Concentra Medical Centers.
                               -------------------------------------------------

3. The  state,  country,  or other  jurisdiction  under the laws of which it was
   incorporated,  organized  or  associated  is Texas,  and the  address  of its
   registered  or  similar  office in that  jurisdiction  is 350 North St.  Paul
   Street, Suite 2900, Dallas, TX 75201.
   -----------------------------------------------------------------------------

4. The period,  not to exceed 10 years,  during  which the assumed  name will be
   used is 10 years.
           ---------------------------------------------------------------------

5. The entity is a (circle one): business corporation,  non-profit  corporation,
   professional  corporation,   professional   association,   limited  liability
   company,  limited  partnership,  registered limited liability  partnership or
   some other type of incorporated  business,  professional or other association
   (specify)

   ----------------------------------------------------------------------------.

6. If the entity is  required  to  maintain a  registered  office in Texas,  the
   address of the  registered  office is 350 North St. Paul Street,  Suite 2900,
   Dallas,  TX 75201 and the name of its registered  agent at such address is CT
   Corporation  System.  The address of the principal office (if not the same as
   the  registered  office) is 5080 Spectrum  Drive,  Suite 400 West,  Dallas TX
   75248.
   -----------------------------------------------------------------------------

7. If the entity is not required to or does not maintain a registered  office in
   Texas, the office address in Texas is _______________________________________
   and if the entity is not incorporated, organized or associated under the laws
   of   Texas,   the   address   of  its   place   of   business   in  Texas  is
   _____________________________________________________________________________
   and  the   office   address   elsewhere   is   ______________________________
   ____________________________________________________________________________.

8. The county or counties where business or  professional  services are being or
   are to be conducted or rendered  under such assumed name are (if  applicable,
   use the designation "ALL" or "ALL EXCEPT"):

   ALL
   ----------------------------------------------------------------------------.

     (Certificate must be executed and notarized on the back of this form.)

<PAGE>

                                             /s/ Richard A. Parr II
                                ------------------------------------------------
                                 Signature of officer, general partner, manager,
                                representative or attorney-in-fact of the entity

                                    Richard A. Parr II
                                    Executive Vice President and General Counsel

Before me on this 12th day of  October,  1998,  personally  appeared  Richard A.
Parr,  II and  acknowledged  to me that  _________  he  executed  the  foregoing
certificate for the purposes therein expressed.

---------------------------------------------------
[Notary Seal Omitted]        BEVERLY MURPHY
                     Notary Public, State of Texas
                    My Commission Expires 6-13-99
---------------------------------------------------

                                                       /s/ Beverly Murphy
                                              ----------------------------------
                                                   Notary Public, State of Texas
                                                                  Beverly Murphy

                INSTRUCTION FOR FILING ASSUMED NAME CERTIFICATE

1.  A corporation,  limited liability company, limited partnership or registered
    limited liability partnership,  which regularly conducts business or renders
    a  professional  service  in this  state  under a name  other  than the name
    contained  in its  articles  of  incorporation,  articles  of  organization,
    certificate of limited partnership or application, must file an assumed name
    certificate  with the  secretary  of state and with the  appropriate  county
    clerk in accordance  with section  36.11 of the Texas  Business and Commerce
    Code.

2.  The information  provided in paragraph 6 as regards the registered agent and
    registered  office  address in Texas must match the  information  on file in
    this office.  To verify the  information  on file with this office,  you may
    contact our corporate  information  unit at (512) 463-5555.  Forms to change
    the  registered  agent/office  are  available  from this  office  should you
    require to update this information.

3.  A certificate executed and acknowledged by an attorney-in-fact shall include
    a statement that the attorney-in-fact has been duly authorized in writing by
    his principal to execute and acknowledge his name.

4.  For  purposes  of filing  with the  secretary  of state,  the  assumed  name
    registrant  should submit an originally  executed  assumed name  certificate
    accompanied  by the filing fee of $25 to the  SECRETARY OF STATE,  STATUTORY
    FILINGS  DIVISION,  CORPORATIONS  SECTION,  P.O.  BOX 13697,  AUSTIN,  TEXAS
    78711-3697.  THE PHONE NUMBER IS (512) 463-5582,  TDD: (800) 735-2989,  FAX:
    (512) 463-5709.

5.  All  assumed  name  certificates  to be filed with the county  clerk must be
    forwarded  directly to the  appropriate  county  clerk by the  assumed  name
    registrant.

6.  Whenever an event  occurs that causes the  information  in the assumed  name
    certificate  to become  materially  misleading  (e.g.  change  of registered
    agent/office or a change of name), a new certificate must be filed within 60
    days after the occurrence of the events which necessitate the filing.

7.  A  registrant  that  ceases to  transact  business  or  render  professional
    services  under an assumed name for which a  certificate  has been filed may
    file an abandonment of use pursuant to the Texas Business and Commerce Code,
    ss.36.14. Forms for this purpose are available from this office.