The Flood of Nordstrand Island
- Describes the circumstances and consequences of the flood of October 1634
- http://home.planet.nl/~snabe003

History of Schleswig-Holstein
- an encyclopedia article on the history from the 19th century, with links to articles on the earlier history of Schleswig and Holstein.
- http://www.infoplease.com/ce6/world/A0860964.html