Steensen, Thomas (2010). "Holländer". Geschichte in Schleswig-Holstein (in German). Gesellschaft für Schleswig-Holsteinische Geschichte. Archived from the original on 18 January 2015.
nordfriiskinstituut.de
"Die Nordfriesen und ihre Sprache" (in German). Nordfriisk Instituut. Archived from the original on 27 September 2007. Retrieved 5 December 2011. Click on the map to access the regional dialects.
"Die Nordfriesen und ihre Sprache" (in German). Nordfriisk Instituut. Archived from the original on 27 September 2007. Retrieved 5 December 2011. Click on the map to access the regional dialects.
Steensen, Thomas (2010). "Holländer". Geschichte in Schleswig-Holstein (in German). Gesellschaft für Schleswig-Holsteinische Geschichte. Archived from the original on 18 January 2015.