TY  - BOOK
AU  - Smith,T.Lynn
AU  - Zopf,Paul E.
TI  - Demography: principles and methods 
SN  - 0803679203
PY  - 1970///
CY  - Philadelphia
PB  - F. A. Davis Co.
KW  - Demography
N1  - Includes bibliographies
ER  -