Calif ICS Press , 1984
Buku Teks
edited by P. Edward Haley, David M. Keithly, and Jack Merritt
Westview Press, 1985
Buku Teks
Robin, Ranger, author
Gage, 1979
Buku Teks
Edward, David V., author
Holt, Rinehart and Winston, 1969
Buku Teks
University press, 1980
Buku Teks