Hale, G E <br/><br/>
Visual Observations of the Solar Atmosphere.  [electronic resource] 

 -  Proceedings of the National Academy of Sciences of the United States of America  May 1926 
 - 286-95 p.  digital 
<br/><br/> Publication Type: Journal Article 
<br/><br/><label>ISSN: </label>0027-8424 
<br/><br/><label>Standard No.: </label>10.1073/pnas.12.5.286  doi