Henderson, Glenn V.
[Publisher not identified], [Date of publication not identified]
Buku Teks
Block, Stanley B.
Irwin, 1994
Buku Teks
Block, Stanley B.
McGraw-Hill, 2002
Buku Teks
Asch, David
Crest Publishing House, 1999
Buku Referensi
Prentice Hall International, 1991
Buku Teks