TY  - BOOK
AU  - Billings,John J.
TI  - The Ovulation method
U1  - 304.632/301.321/BIL 
PY  - 1972///
CY  - Melbourne
PB  - Advocate Press
KW  - Fertility -
KW  - Factors affecting social behaviour population - Fertility -
N1  - Includes references and index
ER  -