Greenlaw, Paul S.
Harper & Row, 1986
Buku Teks
Greer, Charles R., author
Prentice-Hall, 2001
Buku Teks
Gellerman, Saul W.
Penguin Book, 1974
Buku Teks
by Noe, Raymond A. [and others]
McGraw-Hill, 2003
Buku Teks
Scott, Walter Dill, author
McGraw-Hill, 1959
Buku Teks