3William Maher,Chief:Support for Rural America Universal Service and the FCC,Wireline Competition Bureau July 2. 2003 被引量:1
4US NECS(2001).Access in U.S.Public Schools and Classrooms: 1994- 2000 (Statistics in Brief May 2001). http://nces ed.gov/ pubs2001/2001071 .pdf. 被引量:1