(1)  http://www.skydive.com/gallerymain.htm

(2)  http://www.afn.org/skydive/faq/faq.html

(3)  http://www.pbs.org/wgbh/nova/escape/skydive.html

(4)  http://hypertextbook.com/facts/JianHuang.shtml

(5)  http://www.csulb.edu/~gordon/valles.html

(6)  Fundamentals of Physics Extended (textbook)

(7)  http://www.uspa.org/New2Skydiving/Equipment.htm

(8)  http://www.skydive.com/faqs.htm

(9)  http://www.skydivingmagazine.com/ques09.htm