Crano, William D., author
Lawrence Erlbaum Assossiate, 2002
Buku Teks
Goode, William J., author
McGraw-Hill, 1952
Buku Teks
Berg, Bruce L. (Bruce Lawrence), 1954-, author
Pearson, 2004
Buku Teks
edited, Bridget Somekh, Cathy Lewin
Sage Publications , 2005
Buku Teks
Galtung, Johan, author
George Allen and Unwin, 1969
Buku Teks