Ruben, Brent D., author
Kendall Hunt, 2016
Buku Teks
Nan, Lin, author
Bobs-Merril Educations, 1977
Buku Teks
Tubbs, Stewart L., author
Random House, 1974
Buku Teks
Holmes, David, author
Sage, 2005
Buku Teks
Hovland, Carl.I
Yale University Press, 1964
Buku Teks