Fraser, D.A.S., author
John Wiley & Sons, 1967
Buku Teks
Guttman, Irwin, author
John Wiley & Sons, 1982
Buku Teks
Walpole, Ronald E., author
Macmillan, 1972
Buku Teks
Tippett, L. H. C.
Williams and Norgate , 1952
Buku Teks
Hopkins, Kenneth D., author
Allyn And Bacon, 1987
Buku Teks