Literature recommendations for lectures can be found in KIS, on the homepage of the lecture, in the handbook of modules or in OLAT. Usually relevant literature references are given in the lectures.
These recommendations should be available in the library (see course reserves). If this is not the case you can make an acquisition request.
The reserve collection includes books indicated by university lecturers as relevant literature for their seminars. A copy of this recommended reading is placed on a special shelf in the specific department library. This copy cannot be borrowed and is intended for use in the library. In most cases, other borrowable copies are available.
In Landau the reserve collection books tagged with a green sticker and placed on a special shelf at the end or begining of the library section.