Gutteridge, H. C.
Cambridge University Press, 1949
Buku Teks
Hedung, Tilde, author
Routledge, Taylor & Francis Group, 2010
Buku Teks
Norwood, Susan L., author
Prentice-Hall, 2000
Buku Teks
Portney, Leslie Gross, author
Prentice-Hall, 2000
Buku Teks
Gredler, Margaret E., author
The Guilford Press, 2008
Buku Teks