Einstein, A <br/><br/>
On the Relation between the Expansion and the Mean Density of the Universe.  [electronic resource] 

 -  Proceedings of the National Academy of Sciences of the United States of America  Mar 1932 
 - 213-4 p.  digital 
<br/><br/> Publication Type: Journal Article 
<br/><br/><label>ISSN: </label>0027-8424 
<br/><br/><label>Standard No.: </label>10.1073/pnas.18.3.213  doi