Randall, Geoffrey
Crest Publishing House, 2001
Buku Teks
Armstrong, Michael
[Publisher not identified], [Date of publication not identified]
Buku Teks
Riggs, James L.
McGraw-Hill, 1974
Buku Teks
Stryker, Perrin
McGraw-Hill, 1954
Buku Teks
Wiest, Jerome D.
Prentice-Hall, 1969
Buku Teks