Trafton, P. R. (1989). New directions for elementary school mathematics. National Council of Teachers of Mathematics.
Цитирование в стиле Чикаго (17-е изд.)Trafton, Paul R. New Directions for Elementary School Mathematics. Reston, Va.: National Council of Teachers of Mathematics, 1989.
Цитирование MLA (8-е изд.)Trafton, Paul R. New Directions for Elementary School Mathematics. National Council of Teachers of Mathematics, 1989.
Предупреждение: эти цитированмия не могут быть всегда правильны на 100%.