Eldersveld, Samuel J.
Basic Book inc, 1982
Buku Teks
Martin, William J., author
Brookfield, Vt., USA : Gower,, 1995.
Buku Teks
Martin, William J., author
Aslib Gower, 1995
Buku Teks
Clancy, Laurie, 1942-
University of Queensland, 1989
Buku Teks
Bauer, Laurie
Routledge, 1998
Buku Teks