1. Exell , A. W. 1944 Catalogue of the Vascular Plants of S. Tomi
2. Vegetation Belts of the East African Mountains;Hedberg;Svensk. bot. Tidskr.,1951
3. Keay , R. W. J. 1949 An outline of Nigerian Vegetation
4. Lebrun , J. 1935 Les essences forestieres des régions montagneuses du Congo oriental Publ. Inst. Agron. Congo Beige 1
5. The Grassland Vegetation of the Cameroons Mountain;Maitland;Kew Bull.,1932