Hague, Paul, author
Kogen Page, 1994
Buku Referensi
Bogg, Daisy, author
McGraw-Hill, 2012
Buku Teks
edited by Di Lewis
Queensland University of Technology, 1999
Buku Teks
Sklare, Arnold B., author
McGraw-Hill, 1964
Buku Teks
Brown, Leland, author
Prentice-Hall, 1959
Buku Teks