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From Embryology
J E Drumm, R O'Rahilly The assessment of prenatal age from the crown-rump length determined ultrasonically. Am. J. Anat.: 1977, 148(4);555-60 PubMed 868776
J E Drumm, R O'Rahilly The assessment of prenatal age from the crown-rump length determined ultrasonically. Am. J. Anat.: 1977, 148(4);555-60 PubMed 868776