1. Foetal heart frequency and perinatal condition of the foetus and newborn;Hammacher;Gynaecologia,1968
2. Semiquantitative evaluation of antepartum fetal heart rate;Kubli;Int. J. Gynaecol. Obstet,1972
3. The clinical significance of cardiotocography;Huntingsford,1969
4. A new method of fetal heart rate monitoring;Leventhal;Obstet. Gynecol,1975
5. Biophysical neonatal monitoring: Neonatal heart rate;Modanlou;Perinatol. Neonatol,1978