Ruml, Bearsdsley
McGraw-Hill, 1959
Buku Teks
by Jack Canfield ... [and others]
Health Commucations, 1999
Buku Teks
Pauk, Walter, author
Houghton Mifflin, 1984
Buku Teks
Justman, Joseph
Harper & Brithers , 1956
Buku Teks
St. Martin's Press, 1978
Buku Teks