Gentle, James E., editor
Springer, 2012
eBooks
Thyer, Bruce A.
London : Sage Publications, 2001,
Buku Referensi
editor, Bruce A. Thyer
Sage Publications, 2001
Buku Referensi
edited by Nigel G. Fielding; Raymond M. Lee; Grant Blank
SAGE Reference, 2017
Buku Teks
Denton, D. Keith, author
McGraw-Hill, 1992
Buku Referensi