Most books, magazines, newspapers and other media include a publication date. Publication dates are useful for researchers, who need the publication date to cite the material; or even to casual users who want to know when the piece of content was published. Finding publication dates can be easy. However, with the advent of diverse forms of new media like blogs and video, it can get trickier.
Books, Magazines, Newspapers and New Media
Look for the publication date in its standard location. In books, it would be with the other publication information in the front of the book, generally before the table of contents.
Look for the publication date of magazines and newspapers on the cover or, in the case of periodicals, the spine, back page or around the table of contents.
Look for the publication date of new media in a variety of places. Many blog posts list the publication date as a "time stamp" on the post. Videos uploaded to YouTube will display the day they were uploaded.
Note
Be aware that a publication date is often not the same as the date of copyright. If in doubt, contact the publisher of the material.