Grolier Incorporated, 1964
Buku Referensi
edited by Sybil P. Parker
McGraw-HIll, 1995
Buku Referensi
Columbia University Press, 1949
Buku Teks
Browne, G.S., author
F.W. Chesire, 1960
Buku Teks
James, Preston E., author
John Wiley & Sons, 1980
Buku Teks