Coulshed, Veronica, author
Macmillan, 1988
Buku Teks
Zastrow, Charles, author
Dorsey Press, 1985
Buku Teks
Johnson, Louise C., 1923-, author
Allen and Bacon, 1992
Buku Teks
Smalley, Ruth Elizabeth, author
Columbia University Press, 1971
Buku Teks
Davies, liz, author
Learning Matters Ltd., 2008
Buku Teks