1. Altman DG (1991) Practical statistics for medical research, 1st edn. Chapman and Hall, London, pp 258–259
2. Brar HS, Platt LD (1988) Reverse end-diastolic flow velocity of umbilical artery velocimetry in highrisk pregnancies: An ominous finding with adverse pregnancy outcome. Am J Obstet Gynecol 159:449–561
3. Chambers SE, Hoskins PR, Haddad NG, Johnstone FD, McDicken WN, Muir BB (1989) A comparison of fetal abdominal circumference measurements and Doppler ultrasound in the prediction of small-for-dates babies and fetal compromise. Br J Obstet Gynaecol 96:803–808
4. Dempster J, Mires GJ, Patel N, Taylor DJ (1989) Umbilical artery velocity waveforms: poor association with small-for-gestational-age babies. Br J Obstet Gynaecol 96:692–696
5. Fendel H, Fettweis P, Billet P, Werdin R, Sohn C, Giani G, Freiberg C (1987) Doppleruntersuchungen des arteriellen utero-feto-plazentaren Blutflusses vor und während der Geburt. Z Geburtshilfe Perinatol 191:121–129