Green, D.C.
Longman, 1995
Buku Teks SO
editor, Milton Kaufman, Arthur H. Seidman
McGraw-Hill, 1984
Buku Referensi
Hamzah Berahim,
Andi, 1996
Buku Teks SO
Green, D.C.
Longman Scientific & Tecnical, 1992
Buku Teks SO
Stephens, Wendell B.
McGraw-Hill, 1985
Buku Referensi