von Proschwitz, T. 2010. Three land-snail species new to the Norwegian fauna: Pupilla pratensis (Clessin, 1871), Vertigo ultimathule von Proschwitz, 2007 and Balea sarsii Philippi, 1847 [= B. heydeni von Maltzan, 1881]. Fauna norvegica. 30, (Nov. 2010), 13-19. DOI:https://doi.org/10.5324/fn.v30i0.628.