Hartree, Douglas R.  1897-1958 <br/><br/>
Calculating instruments and machines / 
[by] Douglas R. Hartree 
 - Urbana :  University of Illinois Press,  1953 
 - ix, 138 p. ;  25 cm. 
<br/><br/> Includes index 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Calculators<br/>Mathematical instruments