Surface Water and groundwater interaction : a contribution to the hydrological Programme / - París : UNESCO, 1980. - 123´p. : il., map., fot. - Studies and reports in Hydrology ; 29 . Report prepared by the International Commission on Groundwater ISBN: 9231018620 No. de Clasificación Universal Decimal: 551.49: 556.3 (100)=20 SURN.29