Trafton, P. R. (1989). New directions for elementary school mathematics. National Council of Teachers of Mathematics.
Citação do estilo Chicago (17ª ed.)Trafton, Paul R. New Directions for Elementary School Mathematics. Reston, Va.: National Council of Teachers of Mathematics, 1989.
Citação MLA (8ª ed.)Trafton, Paul R. New Directions for Elementary School Mathematics. National Council of Teachers of Mathematics, 1989.
Nota: a formatação da citação pode não corresponder 100% ao definido pela respectiva norma.