go through the view-source and use an emacs macro to look for ''' that isn't '''[[?
Actually, that won't catch pages are (1) unlinked on this page but which, (2) have wiki pages under some other name (than that under which they are listed) or which (3) have a page now but didn't when they were originally added to Music Publishers (usually when people add a page to Category:Music Publishers they remember to add it to this page too, but not always, and Publisher pages aren't always added to the Music Publishers category either... that needs to be watched for!!!!!).