Čar, J. “Heterastridium Conglobatum Reuss, 1865 (?Hydrozoan) in the Norian Limestone of the Kamnik Alps (Slovenia, NW Yugoslavia)”. Geologija, vol. 31, no. 1, June 1988, pp. 199-07, https://www.geologija-revija.si/index.php/geologija/article/view/608.