Breger, Marshall J.
Oxford University Press, 2015
Buku Teks
Yvonne Galligan.
Routledge, 2015
Buku Teks
Mulgan, Richard
Oxford University Press, 1989
Buku Teks
Caprara, Gian Vittorio
Oxford University Press, 2016
eBooks
Woll, Peter
Little, Brown, 1982
Buku Teks