Thorelli, H.B., author
Penguin Books, 1973
Buku Teks
Markin, Rom J., author
John Wiley & Sons, 1982
Buku Teks
edited by Edward C. Bursk and John F. Chapman
New American Library, 1964
Buku Teks
Delong, Thomas, author
McGraw-Hill, 2003
Buku Teks
Heidingsfield, Myron S.
Mass Allyn and Bacon , 1968
Buku Teks