Hole, C.B., author
ELBS and Macmillan Education, 1997
Buku Teks
Sumich, James L., author
Wm.C. Brpwn, 1992
Buku Teks
Daly, Howell V., author
McGraw-Hill, 1978
Buku Teks
Sumich, James L., author
McGraw-Hill, 1999
Buku Teks
Wolfe, Stephen L., author
Wadsworth, 1983
Buku Teks