@book{129949,
	author = {Zulliger, Hans. and Zaragüeta, Juan.},
	title = {Los niños difíciles / },
	editor = {Osca)},
	publisher = {Morata, },
	year = {1952 (},
	series = {Ciencias biológicas},
	address = {Madrid : },
	edition = {1ª ed.}
}