APA (7e ed.) Bronvermelding

Trafton, P. R. (1989). New directions for elementary school mathematics. National Council of Teachers of Mathematics.

Chicago (17e ed.) Bronvermelding

Trafton, Paul R. New Directions for Elementary School Mathematics. Reston, Va.: National Council of Teachers of Mathematics, 1989.

MLA (8e ed.) Bronvermelding

Trafton, Paul R. New Directions for Elementary School Mathematics. National Council of Teachers of Mathematics, 1989.