M. J. Roncada, M. de F. N. Marucci, and I. M. dos R. Lamonica, “ Blood levels of vitamin A and carotene in middle-aged and elderly individuals, in eleven localities of S. Paulo State, Brazil ”, Rev. saúde pública, vol. 19, no. 4, pp. 336–343, Aug. 1985, doi: 10.1590/S0034-89101985000400006.