Template:Ref-PMID868776
From Embryology
Drumm JE. and O'Rahilly R. The assessment of prenatal age from the crown-rump length determined ultrasonically. (1977) Am. J. Anat.: 148(4): 555-60. PMID 868776
Drumm JE. and O'Rahilly R. The assessment of prenatal age from the crown-rump length determined ultrasonically. (1977) Am. J. Anat.: 148(4): 555-60. PMID 868776