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WikiPedia: Bút bi http://inventors.about.com/library/weekly/aa101697... http://www.bicworld.com/en/bic-group/history/ http://www.encyclopedia.com/doc/1G2-2896700021.htm... http://www.fundinguniverse.com/company-histories/B... http://www.google.com/patents/US392046 http://www.herend.com/herald/012/eng/eletmod.htm http://home.howstuffworks.com/pen.htm http://science.howstuffworks.com/question683.htm http://www.ideafinder.com/history/inventions/story... http://www.spacepen.com/about-us.aspx