Annual publications, more often called simply annuals, are periodical publications appearing regularly once per year. Although exact definitions may vary, types of annuals include: Calendars and almanacs, directories, yearbooks, annual reports, proceedings and transactions, and literary annuals. A weekly or monthly publication may produce an Annual featuring similar materials to the regular publication. Some encyclopedias have published annual supplements that essentially summarize the news of the past year, similar to some newspaper yearbooks.