↑Two prenylated flavonoids from the stem bark of Erythrina burttii. Abiy Yenesew, Beatrice Irungu, Solomon Derese, Jacob O. Midiwo, Matthias Heydenreich and Martin G. Peter, Phytochemistry, Volume 63, Issue 4, June 2003, Pages 445–448, doi:10.1016/S0031-9422(03)00209-7