Blyth, Conrad Alexander
Allen & Unwin, 1966
Buku Teks
McClave, James T., author
Prentice-Hall, 2000
Buku Teks
McClave, James T., author
Dellen Publishing, 1979
Buku Teks
Hays, William Lee, 1926-1995, author
Harcourt Brace Colege, 1994
Buku Teks
McClave, James T., author
Dellen Publishing, 1985
Buku Teks