http://www.sheppardsoftware.com/World_Continents.htm
http://www.sheppardsoftware.com/World_G4_name_input.html
http://mrnussbaum.com/continents-and-oceans-game/
http://lizardpoint.com/geography/world-quiz.php
http://www.ezschool.com/Games/SocialStudies/Continents.html