A periodical is a publication that is published periodically like a newspaper a magazine and a journal. Usually periodicals have volume numbers and numbers like V 23 no 45 this information should be included if it is given in addition periodicals have dates of publication like may 3. 2002. Use the same format used for books for multiple authors .
a.Authors Know :Authors last name authors first name title of article in title of periodical volume number place of publication publisher date of periodical section or volume number page numbers of article.
bUnknown Authors: Title of articles in title of periodical volume place of publication; publisher date of periodical section or volume numbers page numbers of article.