1. Bassiakou E, Valsamidis D, Loukeri A, Karathanos A. The distance from the skin to the epidural and subarachnoid spaces in parturients scheduled for caesarean section. Minerva Anestesiol. 2011;77:154–59.
2. Brownridge P. Epidural and subarachnoid analgesia for elective caesarean section. Anaesthesia. 1981;36:70.
3. Coates MB. Combined subarachnoid and epidural techniques. Anaesthesia. 1982;37:89–90.
4. Birnbach DJ, Soens MA. Hotly debated topics in obstetric anesthesiology 2008: a theory of relativity. Minerva Anestesiol. 2008;74:409–24.
5. Fun W, Lew E, Sia AT. Advances in neuraxial blocks for labor analgesia: new techniques, new systems. Minerva Anestesiol. 2008;74:77–85.