@book{250813,
	author = {UNESCO},
	title = {La Naturaleza y sus Recursos : Boletin del Programa sobre el Hombre y la Biosfera},
	publisher = {UNESCO},
	year = {1974},
	address = {Paris},
	note = {-Existencias: 1974 vol. 10, no. 4; 1975 v. 11, no. 1, 4; 1976 v. 12, no. 1, 2, 4; 1977 vol. 13,}
}