@book{52783,
	author = {Worthen, Edmund L. and Aldrich, Samuel R.},
	title = {Suelos agrícolas, su conservación y fertilización},
	publisher = {UTEHA,},
	year = {1959},
	address = {México, D.F. :},
	edition = {2 ed.},
	note = {Trad. de la 5 ed. rev. de 1956}
}