@book{1234,
	author = {Blaug, Mark and Estartús, Mario},
	title = {La teoría económica en retrospección},
	publisher = {Luis Miracle},
	year = {1968},
	address = {Barcelona :},
	url = {https://biblioeco.unsa.edu.ar/pmb/images/libros/La teoria Economica en retrospeccion (l23422).jpg}
}