Zafar, Ahmed, et al. “THROMBOPROPHYLAXIS IN PATIENTS WITH EPIDURAL ANALGESIA AFTER HIP OR KNEE ARTHROPLASTY: Thromboprophylaxis in Epidural Analgesia”. Pakistan Armed Forces Medical Journal, vol. 68, no. 4, Aug. 2018, pp. 822-26, https://pafmj.org/PAFMJ/article/view/90.