Opik, Ernst J.  1893- <br/><br/>
Interplanetary encounters :  close-range gravitational interactions / 
by Ernst J. Opik 
 - Amsterdam :  Elsevier Scientific Pub.,  1976 
 - 155 p. ;  25 cm. 
 - Developments in solar system- and space science ;  2 .
<br/><br/>Includes bibliographical references and index 
<br/><br/><label>ISBN: </label>0444413715 :  PND 67.00 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Celestial mechanics<br/>Gravitation<br/>Planets--Orbits
<br/><br/><label>Dewey Class. No.: </label>521.54