http://speplasticsindustryresource.com/
http://www2.dupont.com/Plastics/en_US/
http://www.dow.com/
http://us.lanxess.com/en/usa-home/
http://www.ticona.com/home/tech/design/general_design.htm
http://www.ashland.com/businesses/adc_na/technical/plastics.asp
http://www.entecresins.com/search/
http://adcats.et.byu.edu/home.php
http://machinedesign.com/article/fundamentals-of-annular-snap-fit-joints-0106
