Exhibit 99.13




                                POWER OF ATTORNEY


     KNOW ALL PERSONS BY THESE PRESENTS that STONE STREET 1998, L.L.C. (the
"Company") does hereby make, constitute and appoint each of Hans L. Reich and
Roger S. Begelman, acting individually, its true and lawful attorney, to execute
and deliver in its name and on its behalf whether the Company is acting
individually or as representative of others, any and all filings required to be
made by the Company under the Securities Exchange Act of 1934, as amended,
giving and granting unto each said attorney-in-fact power and authority to act
in the premises as fully and to all intents and purposes as the Company might or
could do if personally present by one of its authorized signatories, hereby
ratifying and confirming all that said attorney-in-fact shall lawfully do or
cause to be done by virtue hereof.

     THIS POWER OF ATTORNEY shall remain in full force and effect until either
revoked in writing by the undersigned or until such time as the person or
persons to whom power of attorney has been hereby granted cease(s) to be an
employee of The Goldman Sachs Group, Inc. or one of its affiliates.

     IN WITNESS WHEREOF,  the undersigned has duly subscribed  these presents as
of December 16, 1999.


STONE STREET 1998, L.L.C.


By: /s/ Kaca B. Enquist
---------------------------------
Name: Kaca B. Enquist
Title: Vice President