International legend for hydrogeological maps 

 - Paris  1970 
 - 101 p. : ill., (part col.), col. map ; 30 cm. 
<br/><br/> English, French, Russian and Spanish. 
<br/><br/>Bibliography: 79-83. 
<br/><br/><br/>engfrerusspa 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Maps--Symbols<br/>Hydrogeology--Maps--Symbols