CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation by reference of our report included in this Annual Report on Form 10-K, into the Company's previously filed Registration Statements on Forms S-8 (No. 333-562 and 333-566), filed on January 22, 1996. /s/ Arthur Andersen LLP ----------------------- Arthur Andersen LLP Phoenix, Arizona, January 26, 1998. Exhibit 23