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

http://www.jobcosupply.com/catalog/ceramic-heater-elements

http://heateckorea.com/fiberheaters.htm

http://www.allproducts.com/manufacture12/ulamp/square03.html

http://www.tempsensornews.com/control/kapton-heater/

http://www.instructables.com/id/Poor-man-s-200-dollar-plastic-heat-strip-for-penni/