Ulrich's International Periodicals Directory identifies thousands of international periodicals (magazines, journals, newspapers, newsletters, trade journals, etc.) and includes information about the publisher, publishing schedule, readership, subject(s) covered, whether it is refereed, and any special features, e.g. advertising, bibliographies, charts, illustrations, statistics, or book reviews.
Ulrich's also includes reviews from other publications (notably Magazines for Libraries) that provide more information about target audience(s) and what type of libraries might benefit most by including it in their collections.