Thomas Y. Crowell Company, 1962
Buku Referensi
edited by Robert L. Chapman
Harper Collins Publishers, 1992
Buku Referensi
Longmans, 1962
Buku Referensi
Mawson, C. O. Sylvester, author
Garden City Publishing Company, 1940
Buku Referensi
Bolander, Donald O., author
Lexicon, 1993
Buku Referensi