@book{87621,
	author = {Puerto Rico.},
	title = {Lecturas para maestros de noveno grado.},
	publisher = {[s.n.]},
	year = {1957 [i.e. 1956]},
	series = {Its [Publicaciones, Ser. 3-no 103]},
	address = {Hato Rey, P.R.}
}