BOOKS, JOURNALS and VIDEOFILES
Give just the year the work was published. (More specific dates with months or days included are not required.)
Provide a more specific date than simply the year, if available, in cases where new versions of the report may be published in one calendar year, as described in the Magazines, Newsletters, Newspapers section below.
MAGAZINES, NEWSLETTERS, NEWSPAPERS
Give the year and the exact date of the publication (month or month and day), e.g.: (2012, April) or (2008, May 15); if given as a season, give the year and the season, e.g.: (2008, Spring).
WEBSITES AND WEBPAGES (See APA Style's Webpage on a website page).
If the publication date is not clearly mentioned at the beginning of the document, look at the end (e.g. a statement that may say something like: "this document was finalized in 1990...", so that would be the date to use).
If a footer on a webpage says, “This page was last modified on [date]”, then this is NOT the date to use. It COULD be the date that the document was published, but it may also be the date when the webmaster added some code to the page.
Some sites place a copyright date for the website at the bottom of every page. Check a few pages on the site; if the identical statement appears on every page, it’s a site-wide footer, so that’s NOT the date to use. In that case, if no actual publication date can be found, enter (n.d.).
NO DATE AVAILABLE
Use (n.d.) to indicate that there is no date available.
For more information, see section Chapter 9, p. 291.