Siegel, Joel G., author
Macmillan, 1992
Buku Referensi
Garman, E. Thomas, author
Houghton Miffiln, 1985
Buku Teks
Kapoor, Jack R., 1937-, author
McGraw-Hill/Irwin, 2004
Buku Teks
Richards, R. Malcolm, author
Scott, Foresman, 1984
Buku Teks
Unger, Maurice A., author
Allyn and Bacon, 1969
Buku Teks