Pell, Charles Edward. <br/><br/>
The law of births and deaths. 
Being a study of the variation in the degree of animal fertility under the influence of the environment.  By Charles Edward Pell. 
 - London,  T. F. Unwin, ltd.  [1921] 
 - 192 p.  23 cm. 
<br/><br/><label>LCCN: </label>agr22000104  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Fertility.
<br/><br/><label>LC Class. No.: </label>QH471  / .P4