http://pghbridges.com/basics.htm

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

http://www32.brinkster.com/redjeep/bridges/types.htm

http://www.richmangalleries.com/bridges.htm

http://www.crsi.org/transportation/bridge_types.html

http://www.toothpickdesign.com/Bridgetypes.htm

http://www.pbs.org/wgbh/buildingbig/bridge/basics.html

http://www.medicinenet.com/bridges/article.htm

http://www2.co.multnomah.or.us/Public/EntryPoint?ch=f2fd7845ebd96010VgnVCM1000003bc614acRCRD/bridge_types/bridge_types.html

http://www.dentalgentlecare.com/crowns_bridges.htm

http://www.webmd.com/oral-health/dental-health-bridges

http://www.historicbridges.org/b_t_arch.htm