Problems of extra-galactic research :  I.A.U. Symposium No. 15, Aug. 10-12, 1961. 

 - New York :  Macmillan,  [1962]. 
 - xii, 450 p.  ill. 
<br/><br/>Includes bibliogr. references 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Astronomy--Congresses