Haggard, Kristina K.; Tiffney, Bruce H. The Flora of the Early Miocene Brandon Lignite, Vermont, USA. VIII. Caldesia (Alismataceae). American Journal of Botany (American Journal of Botany, Vol. 84, No. 2). 1997, 84 (2): 239–252. JSTOR 2446086. doi:10.2307/2446086.
jstor.org
Haggard, Kristina K.; Tiffney, Bruce H. The Flora of the Early Miocene Brandon Lignite, Vermont, USA. VIII. Caldesia (Alismataceae). American Journal of Botany (American Journal of Botany, Vol. 84, No. 2). 1997, 84 (2): 239–252. JSTOR 2446086. doi:10.2307/2446086.