Prentice-Hall International, 1991
Buku Teks
Block, Stanley B.
Richard D. Irwin, 1994
Buku Teks
Block, Stanley B.
McGraw-Hill, 2002
Buku Teks
Asch, David
Crest Publishing House, 1999
Buku Referensi
Madura, Jeff
Thomson South-Western, 2003
Buku Teks SO