Koupelis, Theo
Jones & Bartlett learning, 2011
Buku Teks
Abell, George O.
Holt Rinehart and Winston, 1974
Buku Teks
Wood, Harley
Angus and Robertson, 1967
Buku Teks
Goldsmith, Donald
Perseus Books, 2000
Buku Teks
Rees, Martin
Basic Books , 1999
Buku Teks