Wiersma, William
Pearson/Allyn and Bacon, 2005
Buku Teks
Wiersma, William
Pearson, 2009
Buku Teks
Zechmeister, Eugene B.
McGraw-Hill, 1992
Buku Teks
Basil Gomez and John Paul Jones III, edited
Wiley-Blackwell, 2010
Buku Teks SO
Alston, Margaret
Allen & Unwin, 1998
Buku Teks