Reference
Boyan Vagalinski, Simeon Borislavov Borissov, Aneliya Bobeva, Giacomo Canciani, Dragan Z. Antic (2022): The mostly cavernicolous millipede genus Stygiiulus Verhoeff, 1929, stat. nov.: taxonomy, distribution and phylogenetic relationships (Diplopoda, Julida, Julidae) – European Journal of Taxonomy – 0798: 30 - 69.