Citazione Stile APA (7a Edizione)

Hamer, J. (1980). The twentieth century (Resource sheets, 1. publ.). MacMillan.

Citazione stile Chigago Style (17a edizione)

Hamer, John. The Twentieth Century. Resource sheets, 1. publ. London [u.a.]: MacMillan, 1980.

Citatione MLA (9a ed.)

Hamer, John. The Twentieth Century. Resource sheets, 1. publ. MacMillan, 1980.