APA

Kretzmann N., . (1965). Elements of formal logic. New York: The Bobbs-Merrill.

Chicago

Kretzmann Norman, . 1965. Elements of formal logic. New York: The Bobbs-Merrill.

Harvard

Kretzmann N., . (1965). Elements of formal logic. New York: The Bobbs-Merrill.

MLA

Kretzmann Norman, . Elements of formal logic. New York: The Bobbs-Merrill. 1965.