At the beginning of each semester, music professors require certain musical works to be reserved for their students. Normally, the works are compiled onto cassette tapes of 60-minute duration for easy access. Students may listen to these tapes in the Listening Library. Reserve tapes do not circulate. Students always have the option to research alternate performances from the ones used on reserve tapes. Staff can assist in this research if needed. Books and scores are reserved by music professors each semester to enhance research and provide additional study material for their students. These items may be checked-out to students for three hours at a time. Some books/scores may circulate overnight if checked-out within an hour of closing time. Some items, such as music reference materials or professors' personal copies, may not be checked-out overnight.