Claringbull, Norman, author
Learning Matters, 2011
Buku Teks
Victoria Clarke, Andrew Walsh, editor
Oxford University Press, 2009
Buku Teks
Evans, Katie, author
Elsevier , 2017
Buku Teks
Donatelle, Rebecca J., author
Pearson, 2014
Buku Teks
Hahn, Dale B., author
McGraw-Hill, 2002
Buku Teks