Publications that are not available in Braunschweig can be ordered via interlibrary loan. You need a valid user card of the UB Braunschweig and a GBV interlibrary loan account (Account activation at the circulation desk).
Do you need a publication within 2 or 3 days? Then you can use the Subito Document Delivery Service. Subito is a fast and uncomplicated fee-based service of German libraries that sends books and copies of articles directly to your private address.