Huntsberger, David V., author
Allyn and Bacon, 1980
Buku Teks
Kozelka, Robert M., author
Addison-Wesley, 1961
Buku Teks
Huntsberger, David V., author
Allyn and Bacon, 1970
Buku Teks
Erickson, Roy V., author
Allyn and Bacon, 1985
Buku Teks
Unesco, 1985
Buku Teks