Lester, James D.
Scott, Foresman and Company, 1971
Buku Teks
Laster, James D
Scott, Foresman and Company, 1984
Buku Teks
Bell, Phillip, author
Sage, 2001
Buku Teks
McInerney, Dennis M., author
Sage Publication, 2001
Buku Teks
Jenkins, Sue, author
Churchill Livingstone, 1998
Buku Teks