@misc{_M_[1937],
 copyright={Public Domain},
 address={Gotha},
 journal={Vogels Karte von Mitteleuropa. Fliegerkarte},
 howpublished={online},
 year={[1937]},
 publisher={Justus Perthes},
 language={ger},
 type={Image},
 title={M 33-NW Dresden},
 URL={http://www.rcin.org.pl/Content/210110/PDF/WA51_191525_PTGC61-17-r1937_M-33-NW-Dresden_0001.pdf},
}