Most of the library's periodicals are now electronic and can be found by searching the library catalog. Current print periodicals are located in three areas. Most of them are located on the east side of the 3rd floor, arranged alphabetically. Theological and religious journals (BL through BX) are located on the 4th floor in the southeast corner. The current issues of very specialized science journals are located in various department reading rooms in the Science Building, DeVries Hall, or the Engineering Building, but older bound volumes are in the Hekman Library. Like books, all bound periodicals are shelved according to the Library of Congress call number system. Periodicals are treated as reference materials and may not be checked out.