Sumner, William Graham,  1840-1910. <br/><br/>
The challenge of facts, and other essays / 
by William Graham Sumner, edited by Albert Galloway Keller 
 - Yale University Press :  New Haven,  1914 
 - xii, 450 p.  port.  23 cm. 
<br/><br/><label>ISBN: </label>0404063039 
<br/><br/><label>LCCN: </label>74-126676 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Social sciences