@misc{_Provinz_[post,
 copyright={Public Domain},
 address={Posen},
 howpublished={online},
 year={[post 1914]},
 publisher={Plandruck-u. Lichtpaus-Anstalt Wilh. Engmann},
 language={ger},
 title={Provinz Posen Masstab 1:500 000},
 keywords={economic maps, Wielkopolska Region, 20th century},
}