For seminars, lectures, and such, the University Library reserves and compiles a set of media for the lecturer. This is called a Semesterapparat. They are usually available at the departmental library that the lecturer is from, for example a lecturer for pedagogy orders a Semesterapparat at the Departmental Library Educational Science, Philosophy, Psychology.
Usually, Semesterapparate are available for the course of a semester. Its books are not for loan and are marked accordingly in the catalogue as well.
Electronic Semesterapparate can be found on StudOn.
For further information, please consult a librarian.