Ellis, Rodney A., author
Thomson, 2003
Buku Teks
Norton, Lin S., author
Routledge, 2009
Buku Teks
Aehlert, Barbara, author
McGraw-Hill, Higher Education, 2007
Buku Referensi
Fasel, Diane K., author
Pathways, 2000
Buku Teks
Matthews, Mark Stanley.
Harper , 1954
Buku Teks