M. C. HOWATSON and IAN CHILVERS. "Tusculum." The Concise Oxford Companion to Classical Literature. 1996. Encyclopedia.com. 16 Nov. 2009 <http://www.encyclopedia.com>.
M. C. HOWATSON and IAN CHILVERS. "Tusculum." The Concise Oxford Companion to Classical Literature. 1996. Encyclopedia.com. (November 16, 2009). http://www.encyclopedia.com/doc/1O9-Tusculum.html
M. C. HOWATSON and IAN CHILVERS. "Tusculum." The Concise Oxford Companion to Classical Literature. 1996. Retrieved November 16, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O9-Tusculum.html