 The rules for CDU Harvard style referencing are particular about punctuation. Most references have four main elements. These are author, year of publication or date, title and source. There is a comma after each surname and author initial, but no comma before the amp sand. There is no comma before the year of publication or date. There is a comma after the year of publication or date. There is a comma after all titles. Little articles put a comma after the journal title. The issue number is in brackets followed by a colon and the page numbers. Add a full stop after the page information. There are single punctuation marks around the article title. Remember that journal titles are in italics. For books, put a comma after the book title and a full stop after the publisher name. More examples, check the CDU Harvard referencing guide.