Johannes CB, Caro JJ, Hartz SC, Marrs R. Adverse effects of ovulatory stimulants: a review. Assist Reprod Rev. 1993;3:68-74.
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.