About two-thirds of the Campus Library’s collection is available in the open stacks and is arranged by subject and according to the Regensburg Classification System (RVK).The RVK system is one of the most widely used subject area systems for research libraries in the German-speaking world. It is organized around the canonical academic fields at German universities, breaking down the arts and sciences into thirty-three subjects or subject groups and assigning each an alphabetized identifier. 

You can find a detailed overview of the RVK system and its subject groups on the University of Regensburg website: https://rvk.uni-regensburg.de/regensburger-verbundklassifikation-online. Please note that there is no complete official English translation of the RVK subject groups.