We have also created a Wikipedia preview box. It works on both desktop & mobile and is very easy to use on any website, including WordPress (there is no plugin yet). As far as I know, it works quite well on the websites (of course, it's not perfect yet).
Project website with examples: su-pa.net/wikiPrevBox/
Git Hub: github.com/su-pa/Wikipedia-preview-boxes
Feedback is warmly welcome.
Dominik