1. Epidural analgesia;Bromage,1978
2. Obstetric anesthesia and analgesia;Moir,1986
3. Cannulation of the epidural space: a comparison of 18- and 16- gauge needles;McNeill;Anaesthesia,1988
4. Anticoagulants and spinal-epidural anesthesia;Vandermeulen;Anesth Analg,1994
5. Intraoperative heparin thromboembolic prophylaxis in primary total hip arthroplasty: a prospective, randomized, controlled, clinical trial;Huo;Clin Orthop,1992