1. Aburel, M.: L'anesthésie du plexus lombo-aortique en obstétrique. Bull. Soc. Obstét. Gynéc. Paris19, 616 (1931).
2. Baptisti, A.: Caudal anesthesia in obstetrics. Amer. J. Obstet. Gynec.38, 462 (1939).
3. Bonica, J.: The management of pain. Philadelphia: Lea and Febiger 1953.
4. Bonica, J.: Principles and practices of obstetric analgesia and anesthesia. Philadelphia: F. A. Davis & Co. 1960/61. Als Autoreferat: An atlas on mechanisms and pathways of pain in labor. What's New. (Abbott Laboratories, North Chicago) No 217, p. 16, 1960.
5. Bush, R. C.: Caudal analgesia for vaginal delivery. Anesthesiology20, 31, 186 (1959).