1. Factors Influencing Planned Delivery
2. R. Caldeiro-Barcia, J. A. Sereno, R. Caldeyro-Barcia, and H. Heller (1961 ): Oxytocin . Perry Press, New York, p177 .
3. J. P. Greenhill, and E. A. Friedman (1974 ): Biological Principles and Modern Practice of Obstetrics . W. B. Saunders and Co, Philadelphia, p199 .