CONSENT OF ARTHUR ANDERSEN, LLP
Published on March 31, 1999
EXHIBIT 23.1
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 (File No. 333-56089), Form S-8 (File No.
333-16837), Form S-3 (File No. 333-16647), Form S-3 (File No. 333-15407), Form
S-3 (File No. 333-60875) and Form S-3 (File No. 333-62855).
/s/ ARTHUR ANDERSEN LLP
Washington, D.C.
March 29, 1999