Dessein & Robbr. (Verdc.) 2001 - Dessein S, Jansen S, Huysmans S, Robbrecht E, Smets E (2001) A morphological and anatomical survey of Virectaria (African Rubiaceae), with a discussion of its taxonomic position. Botanical Journal of the Linnean Society 137(1): 1-29. doi: 10.1111/j.1095-8339.2001.tb01102.x.
There is no corrections for Virectaria major subsp. spathulata yet.