@book{21615,
	author = {Ashburner, John E. and Sims, Brian G.},
	title = {Elementos de diseño del tractor y herramientas de labranza},
	publisher = {Instituto Interamericano de Cooperación para la agricultura,},
	year = {1984},
	series = {Serie de libros y materiales educativos},
	address = {San José, Costa Rica :},
	note = {c.2 rep.}
}