Takeuchi, W. (2011) “Additional notes on Psychotria (Rubiaceae) from the southern karst of Papua New Guinea: P. defretesiana comb. et stat. nov., P. dieniensis var. banakii var. nov., and P. stevedarwiniana sp. nov”, Phytotaxa, 24(1), pp. 19–27. doi: 10.11646/phytotaxa.24.1.3.