@misc{Bertram_Hugo_(1872–1942)_Eindeichung,_1935,
 author={Bertram, Hugo (1872–1942)},
 editor={Schwarz, W. Rys.},
 copyright={Rights Reserved - Restricted Access},
 address={Danzig},
 howpublished={online},
 year={1935},
 publisher={Ottomar Steinbach},
 language={ger},
 title={Eindeichung, Trockenlegung und Besiedlung des Weichseldeltas seit 1300},
 keywords={population maps, historical maps, settlement history, Vistula river delta},
}