Polgar, Stephen, author
Churchill Livingstone, 1988
Buku Teks
Grbich, Carol, author
Allen and Unwin, 1999
Buku Teks
Agnew, Neil McK., author
Prentice-Hall, 1982
Buku Teks
edited by Sharon Andrew, Elizabeth J. Halcomb
Wiley , 2009
Buku Teks
Haselbauer, Kathleen J.
Greenwood Press, 1987
Buku Referensi