<PAGE>
 
                                                                    Exhibit 3(a)


                                   RESTATED

                           ARTICLES OF INCORPORATION

                                       OF

                                GDC GROUP, INC.
                                ---------------

     The undersigned President and Secretary of GDC Group, Inc., a Colorado
corporation (the "Corporation"), adopt the following Restated Articles of
Incorporation, pursuant to the provisions of the Colorado Business Corporation
Act.  These Restated Articles of Incorporation correctly set forth the
provisions of the Articles of Incorporation of the Corporation, as amended, and
they were duly adopted by the board of directors of the Corporation without
shareholder action.  Shareholder approval of these Restated Articles of
Incorporation was not required.

     The Corporation's Articles of Incorporation shall be restated in their
entirety to read as follows:

                                   ARTICLE I
                                   ---------

                                     NAME
                                     ----

     The name of the Corporation shall be GDC Group, Inc.


                                  ARTICLE II
                                  ----------

                              PERIOD OF DURATION
                              ------------------

     The Corporation shall exist in perpetuity, from and after the date of
filing these Articles of Incorporation with the Secretary of State of the State
of Colorado, unless dissolved according to law.

                                  ARTICLE III
                                  -----------
                              PURPOSES AND POWERS
                              -------------------

     1.   Purposes.  Except as restricted by these Articles of Incorporation,
          --------                                                           
the Corporation is organized for the purpose of transacting all lawful business
for which corporations may be incorporated pursuant to the Colorado Corporation
Code.
<PAGE>
 
     2.   General Powers.  Except as restricted by these Articles of
          --------------                                            
Incorporation, the Corporation shall have and may exercise all powers and rights
which a corporation may exercise legally pursuant to the Colorado Corporation
Code.

     3.   Issuance of Shares.  The Board of Directors of the Corporation may
          ------------------                                                
divide and issue any class of stock of the Corporation in series pursuant to a
resolution properly filed with the Secretary of State of the State of Colorado.

                                  ARTICLE IV
                                  ----------
                                 CAPITAL STOCK
                                 -------------

     The total authorized capital stock of the Corporation shall be 90,000,000
shares, of which 70,000,000 shall be common stock and 20,000,000 shall be
preferred stock, all as described below.

     1.   Common Stock.  The aggregate number of voting common shares which this
          ------------                                                          
Corporation shall have the authority to issue is seventy million (70,000,000),
each with two cents ($.02) par value, which shares shall be designated "Common
Stock".  The Common Stock shall have no special powers, preferences or rights,
qualifications, limitations or restrictions.   The rights of holders of shares
of Common Stock to receive dividends or share in the distribution of assets in
the event of liquidation, dissolution or winding up of the affairs of the
Corporation shall be subject to the preferences, limitations and relative rights
of the shares of Preferred Stock fixed in the resolution or resolutions which
may be adopted from time to time by the Board of Directors of the Corporation
providing for the issuance of one or more series of shares of Preferred Stock.

     2.   Preferred Stock.  The aggregate number of preferred shares which this
          ---------------                                                      
Corporation shall have the authority to issue is twenty million (20,000,000)
shares, each with ten cents ($0.10) par value, which shares shall be designated
"Preferred Stock"."

          A.   Shares of Preferred Stock may be issued from time to time in one
     or more series as the Board of Directors of the Corporation (the "Board of
     Directors") may determine. The Board of Directors is hereby authorized, by
     resolution or resolutions, to provide from time to time, out of the
     unissued shares of Preferred Stock not then allocated to any series of
     Preferred Stock, for a series of the Preferred Stock.  Each such series
     shall have distinctive serial designations.  Before any shares of any such
     series of Preferred Stock are issued, 

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<PAGE>
 
     the Board of Directors shall fix and determine, and is hereby expressly
     empowered to fix and determine, by resolution or resolutions, the voting
     powers, full or limited, or no voting powers, and the designations,
     preferences and relative, participating, optional or other special rights,
     and the qualifications, limitation and restrictions thereof. The resolution
     or resolutions providing for the issue of Preferred Stock from time to time
     adopted by the Board of Directors shall be filed with the Secretary of the
     State of Colorado as required by law.

          B.   Each series of Preferred Stock:

          (i)    may have such number of shares;

          (ii)   may have such voting powers, full or limited, or may be without
                 voting powers;

          (iii)  may be subject to redemption at such time or times and at such
                 prices;

          (iv)   may be entitled to receive dividends (which may be cumulative
                 or noncumulative) at such rate or rates, on such conditions,
                 from such date or dates, and at such times, and payable in
                 preference to, or in such relation to, the dividends payable on
                 any other class or classes or series of stock;

          (v)    may have such rights upon the dissolution of, or upon any
                 distribution of the assets of, the Corporation;

          (vi)   may be made convertible into, or exchangeable for, shares of
                 any other class or classes or of any other series of the same
                 or any other class or classes of stock of the Corporation at
                 such price or prices or at such rates of exchange, and with
                 such adjustments;

          (vii)  may be entitled to the benefit of a sinking fund or purchase
                 fund to be applied to the purchase or redemption of shares of
                 such series in such amount or amounts;

          (viii) may be entitled to the benefit of conditions and restrictions
                 upon the creation of indebtedness of the Corporation or any
                 subsidiary, upon the issue of any additional stock (including
                 additional shares of such series or of any other series), and
                 upon the payment of dividends or the making of other
                 distributions on, and the purchase, redemption or other
                 acquisition by this Corporation or any subsidiary of any
                 outstanding stock of the Corporation; and 

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<PAGE>
 
          (ix)   may have such other relative, participating, optional or other
                 special rights, and qualifications, limitations or restrictions
                 thereof;

     all as shall be stated in the resolution or resolutions of the Board of
     Directors providing for the issue of such Preferred Stock.  Except where
     otherwise set forth in the resolution or resolutions adopted by the Board
     of Directors providing for the issue of any series of Preferred Stock, the
     number of shares comprising such series may be increased or decreased (but
     not below the number of shares then outstanding) from time to time by like
     action of the Board of Directors.

          C.   Shares of any series of Preferred Stock which have been redeemed
     (whether through the operation of a sinking fund or otherwise) or purchased
     by the Corporation, or which, if convertible or exchangeable, have been
     converted into or exchanged for shares of stock of any other class or
     classes shall have the status of authorized and unissued shares of
     Preferred Stock and may be reissued as a part of the series of which they
     were originally a part or may be reclassified and reissued as part of a new
     series of Preferred Stock to be created by resolution or resolutions of the
     Board of Directors or as part of any other series of Preferred Stock, all
     subject to the conditions or restrictions on issuance set forth in the
     resolution or resolutions adopted by the Board of Directors providing for
     the issue of any series of Preferred Stock and to any filing required by
     law.

     3.   Dividends.  Subject to the rights of the holders of Preferred Stock,
          ---------                                                           
if any, dividends in cash, property or shares of the Corporation may be paid
upon the Common Stock, as and when declared by the Board of Directors, out of
funds of the Corporation to the extent and in the manner permitted by law.

     4.   Distribution in Liquidation.  Upon any liquidation, dissolution or
          ---------------------------                                       
winding up of the Corporation, and after paying or adequately providing for the
payment of all its obligations and amounts payable in liquidation, dissolution
or winding up and subject to the rights of the holders of Preferred Stock, if
any, the remainder of the assets of the Corporation shall be distributed, either
in cash or in kind, pro rata to the holders of the Common Stock.

     5.   Voting Rights; Denial of Cumulative Voting.  Each outstanding share of
          ------------------------------------------                            
Common Stock shall be entitled to one vote, and each fractional share of Common
Stock shall be entitled to a corresponding fractional vote on each matter
submitted to a vote of shareholders, except that in the election of directors
shareholders shall have the right to vote their Common Stock for as many 

                                      -4-
<PAGE>
 
persons as there are directors being elected with a vote of the Common Stock.
Cumulative voting shall not be allowed in the election of directors of the
Corporation. One-third of the shares entitled to vote, represented in person or
by proxy, shall constitute a quorum at a meeting of shareholders. Except as
otherwise provided by these Articles of Incorporation or the Colorado
Corporation Code, if a quorum is present, the affirmative vote of a majority of
the shares represented at the meeting and entitled to vote on the subject matter
shall be the act of the shareholders. With respect to any action to be taken by
shareholders of this Corporation, when the laws of Colorado require the vote or
concurrence of the holders of two-thirds of the outstanding shares, of the
shares entitled to vote thereon, or of any class or series, such action may be
taken by the vote or concurrence of a majority of such shares or class or series
thereof.

     6.   Denial of Preemptive Rights.   No holder of any shares of the
          ---------------------------                                  
Corporation, whether now or hereafter authorized, shall have any preemptive or
preferential right to acquire any shares or securities of the Corporation,
including shares or securities held in the treasury of the Corporation.

     7.   Transfer Restrictions.  The Corporation shall have the right to impose
          ---------------------                                                 
restrictions upon the transfer of any of its authorized shares or any interest
therein.  The Board of Directors is hereby authorized on behalf of the
Corporation to exercise the Corporation's right to so impose such restrictions.

     8.   One for Twenty Reverse Stock Split.  Effective as of June 14, 1991,
          ----------------------------------                                 
the shareholders of the Corporation approved a one for twenty reverse stock
split of the Corporation's issued and outstanding shares of Common Stock.

     Pursuant to the reverse stock split, twenty shares of the Corporation's
$.001 par value common stock issued and outstanding on June 14, 1991, shall be
changed and reclassified into one share of the Corporation's $.02 par value
common stock.  The capital account of the corporation shall not be increased or
decreased by such change and reclassification.  To reflect such change and
reclassification, each certificate representing shares of $.02 par value Common
Stock theretofore issued and outstanding shall be canceled, and the holder of
record of each such certificate shall be entitled to receive a new certificate
representing one share of common stock for each twenty shares represented by the
original certificates.  Upon this amendment becoming effective, the records of
the Corporation shall be changed to reflect the number of shares owned by each
holder of record after the reverse stock split.  New certificates reflecting
such adjusted number of shares shall be issued to holders of record upon written
request by the holder to the transfer agent, accompanied by the 

                                      -5-
<PAGE>
 
original stock certificate(s). If no written request is received, certificates
reflecting the adjusted number of shares shall be issued to the transferee(s)
upon transfer of such adjusted shares by the current holder of record.

                                   ARTICLE V
                                   ---------
                          INITIAL BOARD OF DIRECTORS
                          --------------------------

     The number of directors shall be fixed from time to time by or in the
manner provided in the bylaws.  So long as the number of directors shall be less
than three, no shares of the Corporation may be issued and held of record by
more shareholders than there are directors.  Any shares issued in violation of
this paragraph shall be null and void.  So long as the number of directors shall
be less than three, this provision also shall constitute a restriction on the
transfer of shares and a legend shall be conspicuously placed on each
certificate respecting shares preventing transfer of the shares to more
shareholders than there are directors.  The name and address of the persons who
initially served as directors were as follows:

          NAME                          ADDRESS
          ----                          -------

          Kenneth A. Larson             1305 Teakwood
                                        Fort Collins, Colorado  80525

          Clarence G. Sitzman           401 Camino Real
                                        Fort Collins, Colorado  80524

          Charles R. Huddleson          215 West Oak Street
                                        Fort Collins, Colorado  80522


                                  ARTICLE VI
                                  ----------
                    TRANSACTIONS WITH INTERESTED DIRECTORS
                    --------------------------------------

     No contract or other transaction between the Corporation and one or more of
its directors or any other corporation, firm, association, or entity in which
one or more of its directors are directors or officers or are financially
interested shall be either void or voidable solely because of such relationship
or interest or solely because such directors are present at the meeting of the
Board of 

                                      -6-
<PAGE>
 
Directors or a committee thereof which authorizes, approves, or ratifies such
contract or transaction or solely because their votes are counted for such
purpose if:

          (a)  The fact of such relationship or interest is disclosed or known
     to the Board of Directors or committee which authorizes, approves, or
     ratifies the contract or transaction by a vote or consent sufficient for
     the purpose without counting the votes or consents of such interested
     directors; or

          (b)  The fact of such relationship or interest is disclosed or known
     to the shareholders entitled to vote and they authorize, approve, or ratify
     such contract or transaction by vote or written consent; or

          (c)  The contract or transaction is fair and reasonable to the
     Corporation.

          Common or interested directors may be counted in determining the
presence of a quorum at a meeting of the Board of Directors or a committee
thereof which authorizes, approves, or ratifies such contract or transaction.

                                  ARTICLE VII
                                  -----------
                            CORPORATE OPPORTUNITIES
                            -----------------------

     The officers, directors and other members of management of the Corporation
shall be subject to the doctrine of corporate opportunities only insofar as it
applies to business opportunities in which the Corporation has expressed an
interest as determined from time to time by the Corporation's Board of Directors
as evidenced by resolutions appearing in the Corporation's minutes.  When such
areas of interest are delineated, all such business opportunities within such
areas of interest which come to the attention of the officers, directors and
other members of management of the Corporation shall be disclosed promptly to
the Corporation and made available to it.  The Board of Directors may reject any
business opportunity presented to it and thereafter any officer, director or
other member of management may avail himself of such opportunity.  Until such
time as the Corporation, through its Board of Directors, has designated an area
of interest, the officers, directors and other members of management of the
Corporation shall be free to engage in such areas of interest on their own and
the provisions hereof shall not limit the rights of any officer, directors or
other member of management of the Corporation to continue a business existing
prior to the time that such area of interest is designated by the Corporation.
This provision shall not be construed to release any 

                                      -7-
<PAGE>
 
employee of the Corporation (other than an officer, director or member of
management) from any duties which he may have to the Corporation.

     As authorized by the Colorado Corporation Code, no Director of the company
shall be personally liable to the Company or any shareholder thereof for
monetary damages for breach of his fiduciary duty as a Director except for
liability for (i) any breach of a Director's duty of loyalty to the company or
its shareholders, (ii) acts or omissions not in good faith or which involve
intentional misconduct to or a knowing violation of law, (iii) acts in violation
of C.R.S. 7-5-114 or any successor legislation, or (iv) any transaction from
which a Director derives an improper personal benefit. This provision shall
apply to a person who has ceased to be a Director of the company with respect to
any breach of fiduciary duty which occurred when such person was serving as a
Director. This provision shall not be construed to limit or modify in any way
any Director's right to indemnification or other right whatsoever under these
Articles, the company's By-Laws or the Colorado Corporation Code. If the
Colorado Corporation Code hereafter is amended to authorize the further
elimination or limitation of the liability of Directors, then the liability of
the Company's Directors, in addition to the limitation on personal liability
provided herein, shall be limited to the fullest extent permitted by the
Colorado Corporation Code as so amended. Any repeal or modification of this
provision by the shareholders shall be prospective only and shall not adversely
affect any limitation on the personal liability of any Director existing at the
time of such repeal or modification.

                                  ARTICLE VIII
                                  ------------
                                INDEMNIFICATION
                                ---------------

     The Corporation may indemnify to the full extent authorized or permitted by
the Colorado Corporation Code any person made, or threatened to be made, a party
to an action, suit or proceedings (whether civil, criminal, administrative or
investigative) by reason of the fact that he, his testator or intestate is or
was a director, officer, employee, fiduciary, or agent of the Corporation or
serves or served any other enterprise at the request of the Corporation.

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<PAGE>
 
                                   ARTICLE IX
                                   ----------
                                   AMENDMENTS
                                   ----------

     1.   The Corporation reserves the right to amend its Articles of
Incorporation from time to time in accordance with the Colorado Corporation
Code. Any proposed amendment shall be adopted upon receiving the affirmative
vote of holders of a majority of the shares entitled to vote thereon, unless the
holders of Preferred Stock are entitled to vote thereon as a class, in which
event the proposed amendment shall be adopted upon receiving the affirmative
vote of the holders of a majority of the shares of Preferred Stock then
outstanding and a majority of the shares of Common Stock then outstanding.

     2.   The holders of the outstanding shares of Preferred Stock shall be
entitled to vote as a class only as required by the Colorado Corporation Code as
in effect from time to time.

                                   ARTICLE X
                                   ---------
                        ADOPTION AND AMENDMENT OF BYLAWS
                        --------------------------------

     The initial Bylaws of the Corporation shall be adopted by its Board of
Directors. The power to alter or amend or repeal the Bylaws or adopt new Bylaws
shall be vested in the Board of Directors, but the holders of Common Stock may
also alter, amend or repeal the Bylaws or adopt new Bylaws. The Bylaws may
contain any provisions for the regulation and management of the affairs of the
Corporation not inconsistent with law or these Articles of Incorporation.

                                   ARTICLE XI
                                   ----------
                     REGISTERED OFFICE AND REGISTERED AGENT
                     --------------------------------------

     The address of the initial registered office of the Corporation is 1580
Lincoln Street, Suite 1125, Denver, Colorado 80203 and the name of the initial
registered agent at such address is David Burlingame. Either the registered
office or the registered agent may be changed in the manner provided by law.

                                      -9-
<PAGE>
 
                                  ARTICLE XII
                                  -----------
                                  INCORPORATOR
                                  ------------

     The name and address of the incorporators are as follows:

          NAME                          ADDRESS
          ----                          -------

          Kenneth A. Larson             1305 Teakwood
                                        Fort Collins, Colorado  80525

          Clarence G. Sitzman           401 Camino Real
                                        Fort Collins, Colorado  80524

          Charles R. Huddleson          215 West Oak Street
                                        Fort Collins, Colorado  80522

DATED the ____ day of January, 1997.


                                        GDC GROUP, INC.


                                        By:   /s/   Harry C. Conger
                                           ----------------------------------
                                        Name: Harry C. Conger
                                        Title: Director, President

                                        By:   /s/ James W. Muzzy
                                           ----------------------------------
                                        Name: James W. Muzzy
                                        Title: Director, Secretary

                                      -10-