Citazione Stile APA (7a Edizione)

Roberts, J. (1992). The penguin history of the world. Penguin.

Citazione stile Chigago Style (17a edizione)

Roberts, J.M. The Penguin History of the World. 3rd.ed: Penguin, 1992.

Citatione MLA (9a ed.)

Roberts, J.M. The Penguin History of the World. Penguin, 1992.