CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

As independent public accountants, we hereby consent to the incorporation of our
reports  included  in  this  Form  10-K  into  the  Company's  previously  filed
registration  statements  on Form S-3 (Nos.  33-65777,  33-65772,  333-32731 and
33-74408) and the registration statements on Form S-8 (Nos. 33-54881, 333-40717,
333-37533,  333-13475,  333-65373, 333-55747, 33-83223, 333-45518, 333-73046 and
33-76496).





                                       /s/ ARTHUR ANDERSEN LLP
                                       ---------------------------
                                           ARTHUR ANDERSEN LLP
Dallas, Texas,
     March 8, 2002