@book{37396,
	author = {Langford, Peter},
	title = {El desarrollo del pensamiento conceptual en la escuela primaria/},
	publisher = {Paidós [etc.]},
	year = {1989},
	series = {Temas de Educación},
	address = {Barcelona [etc.]},
	note = {Bibliogr.: p. 129-154, índices}
}