Kirk, Jerome
Sage Publications, 1989
Buku Teks
Gummesson, Evert
Sage Publications, Inc., 2000
Buku Teks
edited by Peter Reason, Hilary Bradbury
Sage , 2013
Buku Referensi
Steven S. Coughlin, Selina A. Smith, and Maria E. Fernandez, editors
Oxford University Press, 2017
eBooks
Pertti J, Pelto, author
Cambridge University Press, 2012
eBooks