Byrne, David
Routledge, 1998
Buku Teks
Dimitris Ballas, Graham Clarke, Rachel S. Franklin and Andy Newing, authors
Routledge, Taylor & Francis Group, 2018
Buku Teks
Townsend, John C.
McGraw-Hill , 1953
Buku Teks
edited by Diane H. Sonnenwald
Universityy of Texas Press, 2016
Buku Teks
Stebbins, Robert A.
Sage, 2001
Buku Teks