MDPI serves a JS proof-of-work interstitial in place of the article
page, so Find Full Text found nothing. Run the challenge in a hidden
browser when a page's meta refresh points to a registered challenge
host, then retry the page.
Also match meta refresh URL= case-insensitively, since MDPI's is
uppercase, and bound meta refreshes by the redirect limit.
https://forums.zotero.org/discussion/132837/https://forums.zotero.org/discussion/134079/
