1. The Value of ???Multimodal??? or ???Balanced Analgesia??? in Postoperative Pain Treatment
2. Aitken M, Kleinrock M, Lyle J, et al. Medicines use and spending shifts. A review of the use of medicine in the U.S. in 2014. [cited 2016 Apr 11]. Available from: http://www.redaccionmedica.com/contenido/images/IIHI_Use_of_Medicines_Report_2015.pdf
3. The Management of Postoperative Pain Working Group. VHA/DoD Clinical practice guideline for the management of postoperative pain. Version 1.2. Veterans Health Administration, Department of Defence, Washington, DC; May 2002.