Lefton, Lester A.
Allyn and bacon , 1997
Buku Teks
Munn, Norman L., author
Houghton-Mifflin, 1961
Buku Teks
Myers, David G., author
Worth Publisher, 1986
Buku Teks
Myers, David G., author
Worth, 1986
Buku Teks
Papalia, Diane E., author
McGraw-Hill, 1987
Buku Teks