المصادر والمراجع
http://www.uae7.com/vb/t56919.html
http://www.npc-ts.org/article178.html
http://www.faappd.org.jo/AR-CONF4-PAPER-1.htm
http://ayaal-zayd.mam9.com/t26-topic
http://www.mexat.com
http://www.4geography.com/vb/showthread.php?p=19#post