@article{MAN_1888__31_157359,
     author = {Heun},
     title = {Ueber {Euler's} homogenen line\"aren {Multiplicator} zur {Integration} der regul\"aren line\"aren {Differentialgleichungen} zweiter {Ordnung}},
     journal = {Mathematische Annalen},
     pages = {363--373},
     publisher = {mathdoc},
     volume = {31},
     year = {1888},
     zbl = {20.0339.03},
     url = {http://geodesic.mathdoc.fr/item/MAN_1888__31_157359/}
}