APA

Popkin R. H., . (1964). The history of scepticism. New York: Harper and Row.

Chicago

Popkin Richard H, . 1964. The history of scepticism. New York: Harper and Row.

Harvard

Popkin R. H., . (1964). The history of scepticism. New York: Harper and Row.

MLA

Popkin Richard H, . The history of scepticism. New York: Harper and Row. 1964.