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.
Rothman KJ, Velez H, Glass RL, Mejia R, Espinal F. Dental caries and soil contents of trace metals in two Colombian villages. J Dent Res. 1972 Nov 1;51(6):1686.