MARGARET DRABBLE and JENNY STRINGER. "Peter Porcupine." The Concise Oxford Companion to English Literature. 2003. Encyclopedia.com. 10 Dec. 2009 <http://www.encyclopedia.com>.
MARGARET DRABBLE and JENNY STRINGER. "Peter Porcupine." The Concise Oxford Companion to English Literature. 2003. Encyclopedia.com. (December 10, 2009). http://www.encyclopedia.com/doc/1O54-PeterPorcupine.html
MARGARET DRABBLE and JENNY STRINGER. "Peter Porcupine." The Concise Oxford Companion to English Literature. 2003. Retrieved December 10, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O54-PeterPorcupine.html