Fried, Morton H., author
Thomas Y. Crowell, 1968
Buku Teks
Jennings, Jesse D., author
McGraw-Hill, 1972
Buku Teks
Lee Cronk, Vaughn M. Bryant
McGraw-Hill, 2000
Buku Teks
Piddington, Ralph, author
Eidenburgh Oliver , 1960
Buku Teks
Ember, Carol R., author
Prentice-Hall, 1985
Buku Teks