V.  Merckx, Chatrou, L. W., Lemaire, B., Sainge, M. N., Huysmans, S., and Smets, E. F., ?Diversification of myco-heterotrophic angiosperms: evidence from Burmanniaceae?, BMC Evol. Biol., vol. 8:178, pp. 1 - 16, 2008.