1. Bang, J., and Northeved, A., 1972, A new ultrasonic method for transabdominal amniocentesis. Am. J. Obstet. Gynecol. 114:599.
2. Campbell, S., 1968, An improved method of fetal cephalometry by ultrasound, J. Obstet. Gynaecol. Br. Commonw. 75:568.
3. Campbell, S., 1969, The prediction of fetal maturity by ultrasonic measurement of the biparietal diameter, 7. Obstet. Gynaecol. Br. Commonw. 76:603.
4. Campbell, S., 1974a, The assessment of fetal development by diagnostic ultrasound, in:Clinics in Perinatology, Vol. 1, No. 2:Management of the High Risk Pregnancy (A. Milunsky, ed.), p. 507, Saunders, Philadelphia.
5. Campbell, S., 1974b, Fetal growth, Clin. Obstet. Gynecol. 1:41.