3) Sarnat, B. G. & Schour, I.: Enamel hypoplasia (Chronologic enamel aplasia) in relation to systemic disease: A chronologic, morphologic and etiologic classification. J. Am. Dent. Ass., 28: 1989-2000, 1941.
4) Sarnat, B. G. & Schour, I.: Enamel hypoplasia (Chronologic enamel aplasia) in relation to systemic disease: A chronologic, morphologic and etiologic classification. J. Am. Dent. Ass., 29: 67-75, 1942.