Trafton, P. R. (1989). New directions for elementary school mathematics. National Council of Teachers of Mathematics.
芝加哥风格引文Trafton, Paul R. New Directions for Elementary School Mathematics. Reston, Va.: National Council of Teachers of Mathematics, 1989.
MLA引文Trafton, Paul R. New Directions for Elementary School Mathematics. National Council of Teachers of Mathematics, 1989.
警告：这些引文格式不一定是100％准确.