Vertregt, M. <br/><br/>
Principles of astronautic 

 - New York  Elsevier Publishing Company  1960 
 - 221p.  20cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Astronautics
<br/><br/><label>LC Class. No.: </label>TL791.V413 1965