Mallaby, George
Leo Cooper, 1972
Buku Teks
Darwin, Charles Robert
New York Henry Schuman 1950
Buku Teks
Ackerman, Robert
Cambridge University Press , 1990
Buku Teks
Bowering, George
General Publishing , 1983
Koleksi Publik
Cunliffe, Marcus, author
A Mentor Books, 1963
Buku Teks