@misc{_Provinz_1941,
 copyright={Public Domain},
 journal={Ravensteins Bürokarte},
 address={Frankfurt-Main},
 howpublished={online},
 year={1941},
 publisher={Ravensteins Geographische Verlagsanstalt und Druckerei},
 language={ger},
 title={Provinz Ostpreussen : 1:300 000},
 keywords={political-administrative maps, military maps, East Prussia, Masuria, Ermeland},
}