Alex V. Popovkin, Katherine G. Mathews, José Carlos Mendes Santos, M. Carmen Molina, Lena Struwe: Spigelia genuflexa (Loganiaceae), a new geocarpic species from the Atlantic forest of northeastern Bahia, Brazil. In: PhytoKeys. Nr.6, 2011, ISSN1314-2003, S.47–65, doi:10.3897/phytokeys.6.1654.
Alex V. Popovkin, Katherine G. Mathews, José Carlos Mendes Santos, M. Carmen Molina, Lena Struwe: Spigelia genuflexa (Loganiaceae), a new geocarpic species from the Atlantic forest of northeastern Bahia, Brazil. In: PhytoKeys. Nr.6, 2011, ISSN1314-2003, S.47–65, doi:10.3897/phytokeys.6.1654.