Simpson, George Gaylord,   1902-,  <br/><br/>
Tempo and mode in evolution 
Geroge Gaylord Simpson. 
 - New York:  Columbia University Press,  1984. 
 - xxx, 237 pages :   illustrations ;   23 cm 
<br/><br/><label>ISBN: </label>0231058470 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Evolution.