Trafton, P. R. (1989). New directions for elementary school mathematics. National Council of Teachers of Mathematics.
Citación estilo ChicagoTrafton, Paul R. New Directions for Elementary School Mathematics. Reston, Va.: National Council of Teachers of Mathematics, 1989.
Cita MLATrafton, Paul R. New Directions for Elementary School Mathematics. National Council of Teachers of Mathematics, 1989.
Warning: These citations may not always be 100% accurate.