Ziegler, Kathleen, author
Rockport Publishers, 1994
Buku Referensi
Lafosse, Michael G., author
Quarry Books, 1998
Buku Referensi
Cochrane, James C., author
David & Charles , 2008
Buku Teks
Wang, Shaoqiang, chief editor
Page One , 2012
Buku Referensi
Midgley, Barry, editor
Chartwell Books, 1982.
Buku Referensi