May 2006]. Listed as Endangered (EN C2b v2.3). McPherson, S.R. 2009. Pitcher Plants of the Old World. 2 volumes. Redfern Natural History Productions, Poole
of the Old World, Volumes One and Two. Rhodora 112(949): 95–97. doi:10.3119/0035-4902-112.949.95 Darnowski, D. 2010. Pitcher Plants of the Old World.PDF