T. L. P.  Couvreur, Richardson, J. E., Sosef, M. S. M., Erkens, R. H. J., and Chatrou, L. W., ?Evolution of syncarpy and other morphological characters in African Annonaceae: a posterior mapping approach?, Molecular Phylogenetics and EvolutionMolecular Phylogenetics and Evolution, vol. 47, pp. 302-318, 2008.

M.  Botermans, Sosef, M. S. M., Chatrou, L. W., and Couvreur, T. L. P., ?A revision of the African genus Hexalobus (Annonaceae)?, Systematic BotanySystematic Botany, vol. 36, pp. 33-48, 2011.