A periodical is a generic term for anything published periodically; generally, a publication with a distinctive title issued in softcover more than once, usually at regular intervals, without prior decision as to when the final issue will appear. Includes newspapers, newsletters, magazines, and journals. Sold at newsstands and by subscription. Libraries usually bind all the issues which appear during a specific calendar year in a single numbered volume.
Periodicals are published by scholarly societies, university presses, government agencies, commercial publishing houses, private corporations, trade and professional associations, and other organizations. The most comprehensive directory of world periodicals is Ulrich's International Periodical Directory', available in the reference section of libraries in the U.S.
In most libraries, periodicals are shelved alphabetically by title. Back files may be available on microfiche or microfilm to save space. Reader/printer machines and photocopiers are usually available for viewing and making copies. Periodicals published by the U.S. federal government may be shelved by SuDocs number in a separate section for government documents.