The Cambridge companion to Darwin / edited by Jonathan Hodge and Gregory Radick. - Radick, Gregory. (OLS)http://pul/name/50242; Hodge, Jonathan. (OLS)http://pul/name/50241 (University Press, 2009)
Bibliografia: p. 480-520.

L'idea di Europa / Raffaello Morghen. - Morghen, Raffaello, 1896-1983. (OLS)http://pul/name/4542 (ERI, 1968)