According to Scott McLemee of Inside Higher Ed (2013), "broken links in the bibliography are, in effect, broken links in an argument." Said another way, the following error message does not warrant a claim:
A common error message caused by broken links on the World Wide Web
Researchers should avoid using non-persistent links to the World Wide Web as citations and warrants for their claims.
Source: McLemee, S (2013, July 24), In Search of the Missing Link, Inside Higher Ed.