Andrew F. Herrmann, editor
Routledge, Taylor & Francis Group, 2017
Buku Teks
Stefferud, Alfred, editor
United States. Government Printing Office, 1966
Buku Referensi
Wood, Julia T., 1950-, author
Wadsworth and Cengage Learning, 2012
Buku Teks
Schramm, Wilbur, author
Standford University Press, 1961
Buku Teks
Kothari, Ashish
Universities Press, 2007
Buku Teks