Jesness, Jerry, author
Corwin Press, 2004
Buku Teks
National Institute of Educational Planning and Administration , 1985
Buku Teks
National Council of Educational Research and Training, 1983
Buku Teks
Lambirth, Andrew
Learning Matters, 2005
Buku Teks
Ireson, Gren, author
Learning Matters, 2006
Buku Teks