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

http://www.dentalfearcentral.org/laughing_gas.html

http://en.wikipedia.org/wiki/Laughing_Gas_(1914_film)

http://www.laughinggaszone.net/

http://www.laughinggaszone.net/main.html

http://www.laughinggasimprov.com/

http://www.ehow.com/how_5381655_effects-laughing-gas.html

http://www.youtube.com/watch?v=iOkPaSwXC6s

http://www.1stsedationdentist.com/laughing-gas-article27.html

http://www.answers.com/topic/nitrous-oxide