Lutz, Frank W.
Charles E. Merrill Publishing Company, 1969
Buku Teks
Hoy, Wayne K., author
Random House , 1978
Buku Teks
Allyn and Bacon , 1971
Buku Teks
The University of Chicago Press, 1964
Buku Teks
Moehlman, Arthur B.
Houghton Miffiln, 1951
Buku Teks