Slapnik 1991. Distribution of Zospeum alpestre (Freyer 1855), Z. isselianum Pollonera 1886 and Z. alpestre bolei ssp. n. (Gastropoda, Carychiidae) and their variability in the caves in Kamnik and Savinja Alps. Slovenska Akademija Znanosti in Umetnosti Razred za Naravoslovne Vede Razprave, 32 1991: 3-73