TY  - BOOK
AU  - Norton,Mary E.
TI  - Callen's Ultrasonography in Obstetrics and Gynecology 
SN  - 978-0-323-32834-0
U1  - 618.207543 NOR 
PY  - 2017///
CY  - Philadelphia 
PB  -  Elsevier
KW  - Ultrasonics in obstetrics
ER  -