V.  Droissart, Sonké, B., Hardy, O. J., Simo, M., Taedoumg, H., Nguembou, K. C., and Stevart, T., ?Do plant families with contrasting functional traits show similar patterns of endemism? A case study with Central African Orchidaceae and Rubiaceae?, Biodiversity and Conservation, vol. 20, pp. 1507-1531, 2011.