Cambridge University Press , 1988
Buku Teks
Moorehead, Alan, author
Tian xia wen hua chu ban gu fen you xian gong , 1997
Buku Teks
P. F. Collier & Son Corporation, 1959 ; 1969
Buku Referensi
Darwin, Charles Robert
New York Henry Schuman 1950
Buku Teks
Darwin, Charles, author
Penguin Books, 1985
Buku Teks