Ormrod, Jeanne Ellis, author
Pearson Educational, Inc., 2003
Buku Teks
Thurman, Sue, author
Worcestershire , 2011
Buku Teks
Michael Beveridge, editor
Routledge, 2001
Buku Teks
Tilly, Liz, author
Learning Matters, 2011
Buku Teks
J.B. Lippincott Company, 1980
Buku Teks