Answered By: Todd White Last Updated: Jun 22, 2015 Views: 162
If your source has no date it is still important that you acknowledge you looked, but could not find a date.
The way this is done is by using the abbreviation "n.d." (no date) in place of the date -
Author. (n.d.). Title. Retrieved from URL
For a more fleshed-out example of this (in the right-hand column), and for other variations in APA style, see this CSS Library webpage: http://libguides.css.edu/content.php?pid=61826&sid=454616
See also: Publication Manual of the American Psychological Association, 6th ed. p. 185.