T. F. HOAD. "hydrogen." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 30 Nov. 2009 <http://www.encyclopedia.com>.
T. F. HOAD. "hydrogen." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (November 30, 2009). http://www.encyclopedia.com/doc/1O27-hydrogen.html
T. F. HOAD. "hydrogen." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved November 30, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-hydrogen.html