Hughes, Thomas Parke <br/><br/>
Elmer Sperry :  inventor and engineer / 
Thomas Parke Hughes 
 - Baltimore, Md.  The Johns Hopkins University Press  1971 
 - xvi, 348 p. :  ill. ;  25 cm. 
<br/><br/>p. 341-342 
<br/><br/><label>ISBN: </label>0801847567  RM128.64 
<br/><br/><label>Subjects--Personal Names: </label><br/>Sperry, Elmer Ambrose, 1860--1930