Curtis, Graham
Addison-Wesley Publishing Co 1991, 1989
Buku Teks
Cecelja, Franjo
Penton, 2002
Buku Teks
Saldarini, Robert A.
Macmillan Publishing Company, 1990
Buku Teks
Saldarini, Robert A.
Macmillan Publishing Company, 1989
Buku Teks
Kriz, Joseph A.
McGraw-Hill , 1973
Buku Teks