Spencer, P. L. (1952). Building mathematical concepts in the elementary school. Holt.
Chicago (17e ed.) BronvermeldingSpencer, Peter Lincoln. Building Mathematical Concepts in the Elementary School. New York: Holt, 1952.
MLA (9e ed.) BronvermeldingSpencer, Peter Lincoln. Building Mathematical Concepts in the Elementary School. Holt, 1952.
Let op: Deze citaties zijn niet altijd 100% accuraat.