TY  - BOOK
AU  - Keyfitz,Nathan, x
AU  - x
TI  - Introduction  to  the  mathematics  of  population   with  revisions: x
SN  - x    
U1  - 312/KEI 
PY  - 1977///
CY  - .reading 
PB  - Addison-  wesley.
KW  - Population
ER  -