Angel, W. Larsen, author
McGraw-Hill, 2012
Buku Teks
The Nippon Telecommunication Consulting, LTD, 1979
Buku Teks
Traister, John E., author
Reston Publishing Company, 1978
Buku Referensi
editor-in-chief, Larry W. Mays
McGraw-Hill, 2001
Buku Referensi
Thumann, Albert, author
Fairmont Press, Inc., 1987
Buku Teks