Novick D, Montgomery WS, Aguado J, Peng X, Brugnoli R, Haro JM. Which somatic symptoms are associated with an unfavorable course in Chinese patients with major depressive disorder? Asia Pac Psychiatry. 2015 Dec;7(4):427-35. doi: 10.1111/appy.12189
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.