TY  - BOOK
AU  - Billings,Evelyn
TI  - The Billings method: controlling fertility without drug or devices
SN  - 0345341112
U1  - 613.943 
PY  - 1988///
CY  - 
PB  - Ballantine.
KW  - FERTILIDAD
KW  - PLANIFICACION FAMILIAR
N1  - Indice
ER  -