When someone visits a Wikisource page and clicks the "cite this page" link - say on https://en.wikisource.org/wiki/Pogson,_Norman_Robert_%28DNB00%29 - we should be able to provide the citation as "Dictionary of National Biography" with appropriate, author and year information rather than what we produce programmatically. This would probably require that Extension:CiteThisPage be able to read page variables. See also https://www.mediawiki.org/w/index.php?title=Thread:Extension_talk:Cite/Reading_variables_from_the_page_in_Extension:CiteThisPage