1. International Association for the Study of Pain (IASP). IASP Taxonomy. 1994. Available at: www.iasp-pain.org/Taxonomy/. Accessed April 1, 2016.
2. American society for pain management nursing position statement: pain management at the end of life;Reynolds;Pain Manag Nurs,2013
3. World Health Organization. Palliative care fact sheet N°402. 2015. Available at: www.who.int/mediacentre/factsheets/fs402/en/#. Accessed April 1, 2016.
4. Pain assessment in the patient unable to self-report: position statement with clinical practice recommendations;Herr;Pain Manag Nurs,2011
5. The National Consensus Project for Quality Palliative Care. Clinical practice guidelines for quality palliative care, 3rd edition. 2013. Available at: www.nationalconsensusproject.org/guidelines_download2.aspx. Accessed April 4, 2016.