@misc{_N_[1939],
 copyright={Public Domain},
 address={Gotha},
 journal={Vogels Karte von Mitteleuropa. Fliegerkarte},
 howpublished={online},
 year={[1939]},
 publisher={Justus Perthes},
 language={ger},
 title={N 34- SW Warschau-West},
 type={Image},
 URL={http://www.rcin.org.pl/Content/210179/PDF/WA51_191530_PANC61-24-r1939_N-34-SW-Warschau-We_0001.pdf},
}