Ruggiero, V. R. (1991). The art of thinking: A guide to critical and creative thought (3rd.ed.). Harper Collins.
Chicago Style (17th ed.) ZitazioaRuggiero, Vincent Ryan. The Art of Thinking: A Guide to Critical and Creative Thought. 3rd.ed. New York: Harper Collins, 1991.
MLA (9th ed.) ZitazioaRuggiero, Vincent Ryan. The Art of Thinking: A Guide to Critical and Creative Thought. 3rd.ed. Harper Collins, 1991.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.