@book{20019,
	author = {Bonfil, Ramón G.},
	title = {Educación elemental},
	publisher = {Reunión Nacional de Ciencia y Tecnología en la Reforma Agraria,},
	year = {1968},
	series = {Documento C-T-Ref./Agr. IV-39 (3)},
	address = {(México, D.F.) :}
}