Hutchison RW, Anastassopoulos K, Vallow S, Mordin M, Olson W, Hewitt D, Sikirica V. Intravenous patient-controlled analgesia pump and reservoir logistics: results from a multicenter questionnaire. Hosp Pharm. 2007 Nov 1;42(11):1036-44.
Cann CI, Fried MP, Rothman KJ. Epidemiology of squamous-cell cancer of the head and neck. Otolaryngol Clin N Am. 1985 Aug 1;18(3):367-88.