http://www.mansfieldct.org/schools/MMS/staff/hand/Flightfrisbee.htm

http://www.phys.ufl.edu/~upnews/archives/04_12.pdf                       

http://www.physicsclassroom.com/class/newtlaws/u2l3e.cfm             

http://inventors.about.com/library/weekly/aa980218.htm                   

http://www.wrightlife.com/site/store/product-detail/520-pp1/collector_discs/freestyle_discs/

http://img.en.china.cn/0/0,0,121,2929,360,287,eeab6722.jpg