TOM McARTHUR. "ACTIVE (VOICE)." Concise Oxford Companion to the English Language. 1998. Encyclopedia.com. 14 Nov. 2009 <http://www.encyclopedia.com>.
TOM McARTHUR. "ACTIVE (VOICE)." Concise Oxford Companion to the English Language. 1998. Encyclopedia.com. (November 14, 2009). http://www.encyclopedia.com/doc/1O29-ACTIVEVOICE.html
TOM McARTHUR. "ACTIVE (VOICE)." Concise Oxford Companion to the English Language. 1998. Retrieved November 14, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O29-ACTIVEVOICE.html