Bibliography
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Hecht, E. Physics Algebra/Trig. 3rd edition. 2003. Thomson Brooks/Cole. Pacific Grove, California.
Long, J. Climbing Anchors. 1993. The Globe Pequot Press. Guilford, Connecticut.
Beal Ropes. http://www.bealropes.com/english.dir/home.html
Bluewater Ropes. http://spelean.com.au/BW/TM/BWtechmain.html