Jain, S.C., author
Tata McGraw-Hill , 1980
Buku Teks
Middleton, Robert Gordon, 1908-, author
Bombay: D.B. Taraporevala Sons & Private, 1972
Buku Teks
Michael G. Grantham, editor
Routledge, 2011
Buku Teks
Porter, Lindsay, author
Haynes Publishing, 1991
Buku Referensi
Barker, Roger A., author
Psychology Press, 1999
Buku Teks