@book{2904,
	author = {Crespo Pichardo, Guillermo. and Colegio de Postgraduados. Chapingo, Méx. Centro de Edafología. Programa de Agrometeorología.},
	title = {SIACER},
	publisher = {El autor,},
	year = {1991},
	address = {Montecillo, Méx. :},
	note = {D47-198}
}