@book{21137,
	author = {Boonstra, J. and Instituto Internacional de Rescate y Mejoramiento Técnico de Tierras.},
	title = {Numerical modelling of groundwater basins ; a users oriented manual},
	publisher = {International Institute for Land Reclamation and Improvement,},
	year = {(s.a.)},
	series = {ILRI. Publication},
	address = {Wageningen :}
}