2 literature references for Psophocarpus palustris sensu Westphal:

Author: Verdcourt,B. & Halliday,P.
Year: 1978
Title:
Source: Kew Bull.33:191-227. A revision of Psophocarpus.
Author: Westphal,E.
Year: 1974
Title:
Source: Pulses in Ethiopia