400. That’s an error.

Google cannot redirect you to http://worldcat.org/search?q=Nouvelle+biographie+universelle+[afterw.]+générale,+publ.+sous+direction+m.+le+dr.+Hoefer+nouvelle+biographie because the request was invalid.

This might be because the link was created a long time ago. Try your search again on Google. That’s all we know.