I. Jäger-Zürn, “WHAT IS THE DITHECOUS LEAF? AN INVESTIGATION OF THE NEOTROPICAL PODOSTEMUM RUTIFOLIUM SUBSP. RICCIIFORME (PODOSTEMACEAE – PODOSTEMOIDEAE)”, Edinburgh J. Bot., vol. 66, no. 3, pp. 469–481, Oct. 2009, doi: 10.1017/S0960428609990114.