Routledge , 1989
Buku Teks
Runge, Laura L., author
Cambridge University Press, 1997
eBooks
Stratton, Florence
Routledge, 1994
Buku Teks
McDowell, Linda, 1949-, author
Wiley-Blackwell, 2013
Buku Teks
Stearns, Peter N., author
Rontledge, 2006
Buku Teks