Periodicals come in a variety of styles and are published for a variety of audiences.
They offer news, opinion, commentary, scholarly analysis, literary criticism, and reports of research. They range from brief newsletters published by trade organizations to in-depth journals published by scientific societies and university presses. All periodicals are published at regular intervals, from daily newspapers to semi-annual journals. You must make some active choices about the types of periodicals for a given research project. Magazines may be appropriate for some purposes, journals of opinion for others.