http://en.wikipedia.org/wiki/Coil_spring

http://www.coilsprings.com/

http://www.jcwhitney.com/Coil-Springs/600003419.jcw

http://www.kscoilspring.com/

http://www.coilspring.com/index.html

http://en.wikipedia.org/wiki/Spring_(device)

http://www.stengelbros.com/SuperDutyCoilSprings.htm

http://www.car-stuff.com/coilsprings.htm

http://www.zcoil.com/

http://rinovelty.com/index.cfm/fuseaction/products.thumbs/cat/56/Novelties_Coil_Springs