Blackburn, Glenn, author
St. Martin's, 1985
Buku Teks
Rourke, John T., author
McGraw-Hill, 2001
Buku Teks
Kalijarvi, Thorsten V., author
Thomas Y. Crowell, 1954
Buku Teks
Kegley, Charles William, Jr., author
St. Martin`s Press, 1997
Buku Teks
Moon, Parker Thomas, author
Macmillan, 1953
Buku Teks