Computer Technology Research Corp., 1991
Buku Referensi
Murray, Jerome T.
George Allen and Unwin, 1971
Buku Teks
Germain, Clarence B.
Prentice-Hall, 1967
Buku Teks SO
Price, Wilson T.
Rinehart Press, 1968
Buku Teks SO
edited by George McDaniel
McGraw-Hill, 1994
Buku Referensi