Report of the twenty-third session, Czechoslovakia, 1968  general proceedings 
general editor: Miroslav Malkovsky ; edited by Arnost Dudek 
 - Prague  Academia  1970 
 - 227 p. : ill. ; 25 cm. 
<br/><br/><br/>engger 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geology--Congresses