Pasadena : Salem Press., 1994
Buku Referensi
Robert M. Hutchins, Mortimer J. Adler, editors in chief
Encyclopaedia Britannica, Inc., 1963
Buku Referensi
New York Pocket Books 1957
Buku Teks
Arnold, A.
Prentice-Hall, 1996
Buku Teks
Hanes, Bernard
Charles E. Merrill, 1962
Buku Teks