Vitamin A deficiency among brazilian school-aged children in a healthy child service - Custódio, V. I. C.; Daneluzzi, Júlio César; Custódio, R. J.; Del Ciampo, Luiz Antonio; Ferraz, I. S.; Martinelli Júnior, Carlos Eduardo; Ricco, Rubens Garcia; Cupo, Palmira; Hering, Silvia E.; Meirelles, M. S. S.; Vannucchi, Hélio (European Journal of Clinical Nutrition, 2007)