Wriggins, W. Howard
Princeton University Press, 1960
Buku Teks
Tresidder, Argus John
D. Van Nostrand Comp., 1960
Buku Teks
New York Grapic Society, 1957
Buku Referensi
Hulugalle, H.A.J.
Lake House Investments, 1969
Buku Teks
Skinner, Cyril, author
Foris, 1985
Buku Teks