Sources:
- http://www.englishwithjo.com/english-conversation-the-environment/
- http://globalwarming2009.blogspot.com/
- http://www.glogster.com/old/view?nickname=mycau&title=Save-the-Animals/&offset=30
- http://www.koreaittimes.com/image/save-earth
- http://www.dan-dare.org/FreeFun/Games/CartoonsMoviesTV/WALL-E.htm
- http://pixar.wikia.com/WALL%E2%80%A2E_Trivia
- http://www.pastposters.com/details.php?prodId=3665&category=&secondary=27&keywords
- http://en.wikipedia.org/wiki/Hexavalent_chromium
- http://www.osha.gov/SLTC/hexavalentchromium/index.html
- http://www.imdb.com/title/tt0195685/faq
- http://www.google.com/imgres?q=walle/wallpapers/details-of-Lovely-Walle
- http://earthfirst.com/7-environmental-problems-that-are-worse-than-we-thought/
- http://www.usatoday.com/tech/science/2008-10-06-endangered-mammals_N.htm
- http://www.google.com/imgres?q=toxic+chemicals+used+in+industry&hl
- http://www.google.com/imgres?q=hexavalent+chromium&hl
- http://www.google.com/imgres?q=herbicides&hl=en&safe=active&client
- http://www.google.com/imgres?q=second+hand+smoke
- http://www.google.com/imgres?q=mammal+extinction
- http://www.google.com/imgres?q=mammal+extinction&um
- http://www.google.com/imgres?q=toxic+chemical&um
- http://www.google.com/imgres?q=toxic+chemical
- http://www.pq.lung.ca/services/poumon-9/smoke-fumee/
- http://www.worldometers.info/view/toxchem/