Colgate.com, "What is Tartar," http://www.colgate.com/app/Colgate/US/OC/Information/OralHealthBasics/CommonConcerns/PlaqueTartar/WhatisTartar.cvsp (Accessed on February 09, 2007).

ADA.org, "Plaque," http://www.ada.org/public/topics/plaque.asp (Accessed on February 09, 2007).