J. D. Canela, A. C. Lourenço, V. S. Fortes, e A. A. Berretta, “PNS046 Comparative study of antioxidant activity of different propolis extracts (alcoholic, aqueous and dry) by DPPH method”, Rev. Eletr. Farm., vol. 9, nº 1, p. 1, dez. 2012.