1. Statistisches Bundesamt. Gesundheit. Fallpauschalenbezogene Krankenhausstatistik (DRG-Statistik) 2014. Statistisches Bundesamt. Gesundheit. Fallpauschalenbezogene Krankenhausstatistik (DRG-Statistik) 2014. (article in German) https://www.destatis.de/DE/Publikationen/Thematisch/Gesundheit/Krankenhaeuser/FallpauschalenKrankenhaus2120640147004.pdf?__blob=publicationFile.
2. Swedish guidelines for the treatment of pain in tonsil surgery in pediatric patients up to 18 years;E Ericsson;Int J Pediatr Otorhinolaryngol,2015
3. Pain Intensity on the First Day after Surgery: A Prospective Cohort Study Comparing 179 Surgical Procedures;HJ Gerbershagen;Anesthesiology,2013
4. Ketorolac potentiates morphine in postoperative patient-controlled analgesia;P Picard;Pain,1997
5. Use of intravenous patient-controlled analgesia for the documentation of synergy between tramadol and metamizol;A Montes;British Journal of Anaesthesia