Neff, Rose Ann
Wisconsin Magna Publications , 1989
Buku Teks
Bohlin, Lisa, author
McGraw-Hill, 2012
Buku Referensi
Marton, Ference, author
Lawrence Erlbaum Associates, 2004
Buku Teks
Rose, Gillian, author
Sage Publications, 2005
Buku Teks
Galanes, Gloria J., author
McGraw-Hill, 2013
Buku Teks