Digital Equipment Corporation, 1971
Buku Referensi
Hutchings, Howard, author
Butterworth-Heinemann, 1995
Buku Teks
Dixey, Graham, author
Stanley Thornes, 1991
Buku Teks
Dixey, Graham, author
Newnes, 1994
Buku Teks
Artwick, Bruce A.
Prentice-Hall, 1980
Buku Teks