Parker, Raymond L. <br/><br/>
Geochemistry of niobium and tantalum, 
by Raymond L. Parker and Michael Fleischer. 
 - Washington,  U.S. Govt. Print. Off.,  1968. 
 - iii, 43 p.  illus.  29 cm. 
 - United States. Geological Survey. Professional paper  612 .
 - Geological Survey professional paper ;  612. .
<br/><br/>Includes bibliographies. 
<br/><br/><label>LCCN: </label>gs 68000344  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Niobium.<br/>Tantalum.
<br/><br/><label>LC Class. No.: </label>QE75  / .P9 no. 612