Dyfyniad APA

Posnack, E. R. (1946). The 21st centrury looks back. New York: William-Frederick Press.

Dyfyniad Arddull Chicago

Posnack, Emanuel R. The 21st Centrury Looks Back. New York: William-Frederick Press, 1946.

Dyfyniad MLA

Posnack, Emanuel R. The 21st Centrury Looks Back. New York: William-Frederick Press, 1946.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.