Prospectus Supplement No. 12 Filed Pursuant to Rule 424(b)(3)
(To Prospectus Dated November 2, 1999) Registration No. 333-89345
Prospectus Supplement
Dated July 24, 2000
This prospectus relates to the resale by the holders of our:
o $300,000,000 principal amount of 6.25% convertible notes due
2009,
o $425,500,000 principal amount of 2.25% convertible notes due
2009, and
o the shares of Class A common stock issuable upon conversion of
the notes.
This prospectus supplement should be read in conjunction with, and may not be
delivered or utilized without, the prospectus dated November 2, 1999, including
any amendments or supplements thereto. The terms of the notes are set forth in
the prospectus.
The information in the table appearing under the heading "Selling
Securityholders" on page 42 in the prospectus is hereby amended by adding the
information below with respect to selling securityholders not previously listed
in the prospectus or in any amendments or supplements thereto, and by
superceding the information with respect to selling securityholders previously
listed in the prospectus or in any amendments or supplements thereto that are
listed below:
<TABLE>
<CAPTION>
Number of Shares Percentage of
Principal Amount of Class A Common Number of Class A
at Maturity of 6.25% Stock Issuable Shares of Class Common Stock
Notes Beneficially Upon Conversion of A Common Stock Outstanding as
Owned That May the 6.25% Notes That Beneficially of July 19,
Selling Securityholders be Sold May be Sold Owned** 2000***
------------------------- ------------------- ------------------- --------------- --------------
<S> <C> <C> <C> <C>
Putnam Balanced Retirement Fund $28,000 1,147 -- *
Putnam Convertible Opportunities and Income Trust $36,000 1,475 -- *
Museum of Fine Arts, Boston $14,000 573 -- *
ProMutual $50,000 2,049 -- *
University of Rochester $13,000 532 -- *
Parker-Hannifin Corporation $24,000 983 -- *
=========== ======= === ==
TOTAL $165,000 6,759 -- *
<FN>
* Less than 1%.
** In addition to the shares issuable upon conversion of the notes.
*** Includes shares issuable upon conversion of the notes and additional shares beneficially owned as of July 19, 2000.
</FN>
</TABLE>
