Heimstra, Norman W., author
Brooks/Cole, 1974
Buku Teks
by Paul A. Bell ... [and others]
Wadsworth/Thomson Learning, 2001
Buku Teks
Bell, Paul A., author
Thomson, 2001
Buku Teks
edited by Linda Steg, Agnes E. van den Berg, Judith I.M. de Groo
BPS Blackwell, 2013
Buku Teks
Kopec, David Alan, author
Fairchild Books, 2012
Buku Teks