TY  - JOUR 
T1  - Serial echocardiographic assessment of evolution of ductus arteriosus in preterm infants
JO  - einstein (São Paulo)
A1  - Bai-Horng, Su
SN  - 1679-4508
UL  - 10.1590/S1679-45082014CE3052
VL  - 12 
Y1  - 2014
PB  - Brasil 
ER  -