Reference
Maria Ansaldi, Jost S. Casper (2009): Pinguicula mariae Casper nova spec. and Pinguicula apuana Casper et Ansaldi nova spec. - A contribution to the occurrence of the genus Pinguicula L. (Lentibulariaceae) in the Apuan Alps (Italy) – Wulfenia – 16: 1 - 31.