APA

Spencer H., .First principles. New York: De Witt Revolving Fund, Inc., 1958.

Chicago

Spencer Herbert, .First principles. New York: De Witt Revolving Fund, Inc., 1958.

Harvard

Spencer H., .First principles. New York: De Witt Revolving Fund, Inc., 1958.

MLA

Spencer Herbert, .New York: De Witt Revolving Fund, Inc., 1958. .