CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation of our report included in this Form 10-K into the Company's previously filed registration statements on Form S-8 (Nos. 333-87915, 333-87913, 333-52701, 333-38133, 333-21831, 033-59465, 033-59461). /S/ Arthur Andersen LLP Dallas, Texas, March 29, 2000