Palmer, Alan, author
Penguin Books , 1987
Buku Referensi
Crawfurd, John, author
Oxford University Press, 1971
Buku Referensi
Schapiro, J. Salwyn
McGraw-Hill Book Company, Inc., 1950
Buku Teks
editor, Ainslie T. Embree
Charles Scribner's Sons, 1988
Buku Referensi
edited by M. Cary
Clarendon Press, 1950
Buku Referensi