National Geographic Vol. 225, no.4 April 2014 How our universe began 

 - Washington, D.C. :  National Geographic Society,  2014 
 - 142p.  26cm 
<br/><br/><label>ISSN: </label>0027 9358 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geography -- Periodicals