Terrell (A.Gray) 2002 - Terrell EE (2001) TAXONOMIC REVIEW OF HOUSTONIA ACEROSA AND H. PALMERI, WITH NOTES ON HEDYOTIS AND OLDENLANDIA (RUBIACEAE). Sida, Contributions To Botany 19(4): 913-922. Retrieved from http://www.jstor.org/stable/41967943
There is no corrections for Houstonia acerosa var. polypremoides yet.