Davis, Williams, author
Addison-Wesley, 1983
Buku Teks
Kendall, Penny A., author
Irwin , 1996
Buku Teks
Cutts, Geoff, author
Alfred Waller, [date of publication not identified]
Buku Teks
Hare, Van Court, author
Harcourt, Brace and World, 1967
Buku Teks
Davis, William S., author
Addison-Wesley, 1983
Buku Teks