F.  Verloove, ?Verbena incompta (Verbenaceae), an overlooked xenophyte in Europe ?, Willdenowia, vol. 41, pp. 43-49, 2011.

F.  Verloove and Reynders, M., ?Studies in the genus Paspalum (Paniceae, Poaceae) in Europe ? 2. The Quadrifaria group?, Willdenowia, vol. 37, pp. 423-430, 2007.