Dekker, Sidney W. A., author
Lawrence Erlbaum Associates, 2005
Buku Teks
Dekker, Sidney, author
CRC Press, 2015
Buku Teks
United Nations , 1987
Buku Teks
Howes, Mary B.
Academic Press, 2014
eBooks
Kantowitz, Barry H., author
John Wiley & Sons, 1983
Buku Teks