Filchner, Wilhelm <br/><br/>
Route-mapping and position-locating in unexplored regions 
Wilhelm Filchner 
 - New York :  Academic Press,  1957. 
 - 288p. :  ill. ;  25 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Surveying<br/>Orientation
<br/><br/><label>LC Class. No.: </label>TA625.F52