Hardgrave, Robert L., author
Harcourt, Brace, 1970
Buku Teks
McKenna, George, author
McGraw-Hill, 1998
Buku Teks
Shea, John C.
St. Martin's Press, 1984
Buku Teks
Sharan, P.
Metropolitan, 1984
Buku Teks
Hardgrave, Robert L., author
Harcourt College, 2000
Buku Teks