APA aipamena

Petroski, H. (1992). The pencil: A history of design and circumstance. New York: Alfred A. Knoff.

Chicago Style aipamena

Petroski, Henry. The Pencil: A History of Design and Circumstance. New York: Alfred A. Knoff, 1992.

MLA aipamena

Petroski, Henry. The Pencil: A History of Design and Circumstance. New York: Alfred A. Knoff, 1992.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.