McElroy, Ann, author
Westview Press, 1996
Buku Teks
Young, Clarence W., author
Harper & Brothers, 1956
Buku Teks
Inglis, J.K., author
Pergamon Press , 1974
Buku Teks
Burnet, Macfarlane
St. Martin's Press, 19770
Buku Teks
Treshow, Michael, author
McGraw-Hill, 1976
Buku Teks