Reference

L. Anders Nilsson, Lars J. Jonsson, Lydia Rason, Emile Randrianjohany (1985): Pollination of Plectranthus vestitus (Lamiaceae) by Trap-Lining Hovering Bees in Madagascar – Österreichische Botanische Zeitschrift = Plant Systematics and Evolution – 150: 223 - 236.