@article{CMH_1943__16_138842,
     author = {H. Hadwiger},
     title = {Eine elementare {Ableitung} der isoperimetrischen {Ungleichung} f\"ur {Polygone.}},
     journal = {Commentarii mathematici Helvetici},
     pages = {305--309},
     publisher = {mathdoc},
     volume = {16},
     year = {1943},
     zbl = {0061.38203},
     url = {http://geodesic.mathdoc.fr/item/CMH_1943__16_138842/}
}