Editors. "Richelieu tries to unite Sweden and Catholic League against the Habsburgs". The Literary Encyclopedia. First published 01 February 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=16000, accessed 21 May 2013.]
Richelieu, who has just mediated a truce between Sweden and Poland, tries to unite Sweden and the German Catholic League in an alliance against the House of Habsburg.