Crowther, J.G.. <br/><br/>
Discoveries and Inventions of the 20th Century /  Textual Documents 
J.G.Crowther. 
 - 4th Rev. ed. / 
 - London :  Routledge and Kegan Paul ,  1955. 
 - 432p. :  ill ;  22cm . 
<br/><br/><label>Subjects--Index Terms: </label>Science and Technology Discoveries-20th Century Inventions-20th Century G-Mathematics 
<br/><br/><label>Dewey Class. No.: </label>509  / C 886 D