Mauskopf JA, Candrilli SD, Chevrou-Severac H, Ochoa JB. Immunonutrition for patients undergoing elective surgery for gastrointestinal cancer: impact on hospital costs. World J Surg Oncol. 2012 Jul 1;10:136.
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.