Citation, Documentation of Sources

Q. How would you treat web page citations where access to the web pages is restricted?

A. So much internet content—after connection costs and the price of hardware and software—still seems to be free. But before this age of “free” access to thousands of newspapers and scores of ancient, out-of-copyright works, you could still cite, for example, the Journal of the American Medical Association, a subscription to which has probably never been free. And just as we don’t recommend including costs and availability in citations to books or journals, we don’t require or recommend any statement related to accessibility when citing an internet source. For one thing, the status and location of online material is so often subject to change that any such information is likely to become obsolete and possibly misleading. And, as has long been the case, libraries can provide access to many materials that may not be available to individuals.

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]