Hydrological observation explained pictures 

 -  1985. 
 - 2 vol. 
<br/><br/>V1. Rainfall and water level observation;V2. Discharge observation 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Precipitaciones
<br/><br/><label>Universal Decimal Class. No.: </label>556.12