Dipboye, Robert L.
Harcourt Brace College, 1994
Buku Teks
edited by A.A. Myers and P.S. Giller
Chapman & Hall, 1988
Buku Teks
Alcock, John
Sinauer Associates, 1989
Buku Teks
Rosenthal, Murray P.
Hayden Book , 1975
Buku Teks
edited by R.I. Freshney
IRL Press, 1992
Buku Teks