@article{MAN_1919__79_158796,
     author = {O. Haupt},
     title = {\"Uber lineare homogene {Differentialgleichungen} 2. {Ordnung} mit periodischen {Koeffizienten}},
     journal = {Mathematische Annalen},
     pages = {278--285},
     publisher = {mathdoc},
     volume = {79},
     year = {1919},
     zbl = {46.0666.03},
     url = {http://geodesic.mathdoc.fr/item/MAN_1919__79_158796/}
}