At the request of Wikipedia editors, a new feature has been added to MediaWiki. Long lists of references (also called citations or footnotes) will automatically be displayed in columns. This will make it easier for most people to read the references, especially on narrow screens. Short lists of references will not be affected.
I plan to enable this new feature at this wiki on Monday, 11 September 2017. After that date, use the normal <references /> tag on any page with many references to see this feature. If you do not want columns used on that page, then use this wikitext code instead: <references responsive="0" />