Jackson, Donald Dale <br/><br/>
Underground worlds / 
Donald Dale Jackson 
 - Alexandria, Va. :  Time-Life Books,  1982 
 - 176 p :  ill 
 - Planet earth : 6 .
<br/><br/><label>ISBN: </label>0809443201 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Caving--History--19th century<br/>Caving--History--20th century<br/>Caves
<br/><br/><label>LC Class. No.: </label>GB601.3  / J12 U5 1982