Rothman KJ, Glass RL, Espinal F, Velez H. Caries-free teeth in the absence of fluoride ion. J Public Health Dent. 1972;32(4):225-8. doi: 10.1111/j.1752-7325.1972.tb03977.x

Dr. Rothman and his group present a finding in two nearby villages of Colombia that no factor could explain a markedly low DMFS in the village of Heliconia.