Wood, Frederick T.
Macmillan, 1964
Buku Teks
Dixson, Robert J., author
Regents Publishing, 1981
Buku Referensi
Shaw, Harry, author
McGraw-Hill, 1975
Buku Referensi
Perkins, Michael R., author
Frances Pinter, 1983
Buku Teks
Laurence Urdang, editor in chief
Gale Research Company, 1983
Buku Referensi