Kagan, Shelly, author
Westview Press, 1997
Buku Teks
Badger, Walter L. (Walter Lucius), 1886-1958, author
McGraw-Hill, 1957
Buku Teks
Hay, William W., author
John Wiley & Sons, 1977
Buku Teks
Hay, William W., author
John Wiley & Sons, 1961
Buku Teks
Khisty, C. Jotin, author
Prentice-Hall, 1990
Buku Teks