Observatory : Review Of Astronomy 

 - Oxford  Vincent Baxter Press  1949 
 - 240 
 - Nos. 848-53 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>B9m3151,M81
<br/><br/><label>Dewey Class. No.: </label>B9m3151,M81  / B1.70