Weintraub, Stanley, 1929-
Doubleday, 1964
Buku Teks SO
Carrel, Alexis
Penguin Books, 1967
Buku Teks SO
Begley, Louis
Ballentine Books, 1996
Buku Teks
Böll, Heinrich
Koln Friedrich Middelhauve c1951
Buku Teks
Carnegie, Dale, 1888-1955
New York :Dake Carnegie & associates, Inc. ,1999,
Buku Teks