1. S. Bachman and J. Moat "Bot. Gard. Conserv. Int. J." 9, "GeoCAT – an open source tool for rapid Red List assessments." (2012)
2. S. Cable and M. Cheek "The plants of Mount Cameroon: a conservation checklist." (1998)
3. M. Cheek, B.J. Pollard, I. Darbyshire, et al. "The plants of Kupe, Mwanenguba and the Bakossi Mountains, Cameroon: a conservation checklist." (2004)
4. "Landscapes of West Africa: A window on a changing world." (2016)
5. F.J.H. van Dilst, "Bull. Jard. Bot. Natl. Belg." 64, "Baissea A. DC. Series of Revisions of Apocynaceae XXXIX." 89 (1995)