Rate and direction of inventive activity : Economic and social factors 
A Conference of the Universities-National Bureau Committee for Economic Research and. The Committee on Economic Grwoth of the Social Science Research Council; A Report of the National Bureau of Economic Rsearch, New York 
 - Princeton   Princeton University Press  1962 
 - x,633p. 
<br/><br/><label>Source: </label>Textual 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Economics