Perkins, Dexter
Harvard University Press, 1954
Buku Teks
Sandman, Peter M., author
Prentice-Hall, 1976
Buku Teks
Bartlett, Ruhl
Hill and Wang, 1963
Buku Teks
Uffenbeck, John E., author
Prentice-Hall, 1982
Buku Teks
Perry, Michael J.
Oxford University Press, 1997
Buku Teks