Gaya APA

DiLeo, W., Towers, V, F. (1991). THE ENCYCLOPEDIA AMERICANA 21 (Oporto To Photoengraving) (1). Americana Corporation, New Yor: Grolier Incorporated.

Gaya MLA

DiLeo, Warren., Towers, Veronica, F.. "THE ENCYCLOPEDIA AMERICANA 21 (Oporto To Photoengraving)". 1 Americana Corporation, New Yor: Grolier Incorporated, 1991. Ensiklopedi.