APA (7e ed.) Bronvermelding

WALKER, H. M. (1951). Mathematics essential for elementary: Statistics; a self-teaching manual. Holt, Rinehart and Winston.

Chicago (17e ed.) Bronvermelding

WALKER, Helen M. Mathematics Essential for Elementary: Statistics; a Self-teaching Manual. New York: Holt, Rinehart and Winston, 1951.

MLA (9e ed.) Bronvermelding

WALKER, Helen M. Mathematics Essential for Elementary: Statistics; a Self-teaching Manual. Holt, Rinehart and Winston, 1951.