The University Library uses the 'Regensburger Verbundklassifikation' (RVK) as its classification scheme.
You can look up subject codes for the classification scheme in Regensburg Verbundklassifikation Online.
The notation is the part of the shelf mark that says something about the content of the book. For instance, in the shelf mark 65/HR 1010 H816, the notation HR 1010 stands for 'General literature, compendia, authors' handbooks for English and American Studies'
The majority of holdings are openly accessible in the reading rooms or the Book Tower. The Regensburg classification scheme ensures that related topics are located next to each other. Borrowing from the reading room collection
A large part of the holdings is not freely accessible but located in the closed stacks. Items from the stacks must be requrested in InfoGuide and then fetched from the collection area or the check-out desk of the Regional Library, as indicated in the request. Borrowing from the closed stacks
Books and other media with three-digit location codes are part of a professor's reserve collection. To access these items you will generally have to contact the relevant professor's office.