Piet Stoffelen; Martin Cheek; Diana Bridson; Elamr Robbrecht (1997). "A new species of Coffea (Rubiaceae) and notes on Mount Kupe (Cameroon)". Kew Bulletin. 52: 989–994. doi:10.2307/4117826. JSTOR4117826.
jstor.org
Piet Stoffelen; Martin Cheek; Diana Bridson; Elamr Robbrecht (1997). "A new species of Coffea (Rubiaceae) and notes on Mount Kupe (Cameroon)". Kew Bulletin. 52: 989–994. doi:10.2307/4117826. JSTOR4117826.