Frankel,Theodore. <br/><br/>
Gravitational curvature  an introduction to einstein's theory 
by Theodore Frankel 
 - San Francisco  W.H.Freeman and Company  1979 
 - xviii, 172p. 
<br/><br/><label>ISBN: </label>0716710625 
<br/><br/><label>Dewey Class. No.: </label>530.11  / N791