Standard LaTeX will only switch between \onecolumn and \twocolumn at the top of a page; the commands themselves clear the previous page. This package does away with the restriction, and allows you to mix one- and twocolumn modes on the same page.
The package is part of the sttools bundle.
The author is Sigitas Tolušis. The package is Copyright © 2012 Sigitas Tolušis.
License: lppl1.3 Version: 1.5 Catalogued: 2015-08-03