@article{MAN_1964__156_161202,
     author = {W.N. EVERITT},
     title = {Singular {Differential} {Equations} {I:} {The} {Even} {Order} {Case.}},
     journal = {Mathematische Annalen},
     pages = {9--24},
     publisher = {mathdoc},
     volume = {156},
     year = {1964},
     zbl = {0145.10902},
     url = {http://geodesic.mathdoc.fr/item/MAN_1964__156_161202/}
}