Prospectus Supplement No. 4 Filed Pursuant to Rule 424(b)(3)
(To Prospectus Dated November 2, 1999) Registration No. 333-89345
Prospectus Supplement
Dated December 16, 1999
This prospectus relates to the resale by the holder of our:
o $300,000,000 principal amount of 6.25% convertible notes due 2009,
o $425,500,000 principal amount at maturity 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:
Principal Percentage Number of
Amount at of 6.25% Shares of Class Percentage of
Maturity of Notes A Common Stock Number of Class A Common
6.25% Notes Outstanding Issuable Upon Shares of Stock
Beneficially as of Conversion of Class A Outstanding as
Owned That December 14, the 6.25% Notes Common of December
Selling Securityholders May Be Sold 1999 That May Be Sold Stock Owned 14, 1999**
----------------------- ----------- ------------ ---------------- ----------- --------------
General Motors Employees Global Group Pension Trust $5,322,000 2.25 218,114 -- *
Morgan Stanley Dean Witter(1) $1,730,000 * 70,901 -- *
========== =========== ================ =========== ==============
TOTAL $7,052,000 2.99 289,015 -- *
Principal Percentage Number of
Amount at of 2.25% Shares of Class Percentage of
Maturity of Notes A Common Stock Number of Class A Common
2.25% Notes Outstanding Issuable Upon Shares of Stock
Beneficially as of Conversion of Class A Outstanding as
Owned That December 14, the 2.25% Notes Common of December
Selling Securityholders May Be Sold 1999 That May Be Sold Stock Owned 14, 1999**
----------------------- ----------- ----------- ---------------- ----------- --------------
Forrestal Funding Master Trust $14,000,000 4.75 583,333 -- *
* Less than 1%.
** Includes shares issuable upon conversion of the notes and shares beneficially
owned as of December 14, 1999.
(1) Morgan Stanley & Co. Incorporated, an affiliate of Morgan Stanley Dean
Witter, was an initial purchaser of the notes when the notes were originally
sold in a private placement.
