McAshan, H. H. (Hildreth Hoke)
McGraw-Hill, 1963
Buku Teks
Hodgson, Naomi, author
West Sussex, UK Wiley Blackwell, 2016
Buku Teks
edited by Christina Hughes
Open University Press, 2003
Buku Teks
Marvin C. Alkin, editor-in-chief
MacMillan Library Reference USA, 1992
Buku Referensi
Lodico, Marguerite G., author
Jossey-Bass, 2010
Buku Teks