United Nations,Department of economic and social affairs. <br/><br/>
Levels and trends of fertility through out the world, 1950 -1970 /United Nations 

 - New York  United Nations  1977 
 - xiii, 361p. 
 - Population studies .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Demography<br/>Fertility