(DE) S. J. Casper, Monographie der Gattung Pinguicula, Stoccarda, Bibliotheca Botanica, Heft 127/128, 1966.
(EN) Thomas Cieslak, et al, Phylogenetic analysis of Pinguicula (Lentibulariaceae): chloroplast DNA sequences and morphology support several geographically distinct radiations, in Am. J. Bot., vol. 92, 2005, pp. 1723-1736. Abstract