M. D.  Pirie, Kankainen, S., and Maas, P. J. M., ?Revision and phylogeny of Cremastosperma (Annonaceae)?, in Cremastosperma (and other evolutionary digressions). Molecular, phylogenetic, biogeographic, and taxonomic studies in Neotropical Annonaceae, M. D.  Pirie, Ed. Utrecht: PhD-thesis, Utrecht University, 2005, pp. 87-188.