Saldarini, Robert A., author
Macmillan, 1990
Buku Teks
Martin, Merle P., author
Macmillan, 1991
Buku Teks
Saldarini, Robert A., author
Macmillan, 1989
Buku Teks
Curtis, Graham
Addison-Wesley Publishing Co 1991, 1989
Buku Teks
Rao, Venkata
Times Books International , 1979
Buku Teks