Editors. "The Great Elector of Brandenburg aids the Danes". The Literary Encyclopedia. First published 01 April 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=16445, accessed 21 May 2013.]
Charles X of Sweden has been besieging the Danish capital Copenhagen since the previous month, but now Frederick William, the Great Elector of Brandenburg, comes to Denmark's aid by blockading the Swedes.