Ribeiro, V.G. et al. (2000) “Effects of gibberellic acid (GA3) and activated coal on in vitro culture of Citrus limonia Osbeck x Poncirus trifoliata L. Raf. embryos”, Pesquisa Agropecuaria Brasileira, 35(1), pp. 27–30. doi:10.1590/S1678-3921.pab2000.v35.5682.