The Nss Bulletin: Journal of caves and karst studies / 
National Speleological Society. 
 -- Huntsville :   The National Speleological Society  
 - 1974-- . -- 
<br/><br/>ISSN 0146-9517 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Espeleologia<br/>Cuevas
<br/><br/><label>Universal Decimal Class. No.: </label>551.44(05)