@article{GDZPPN002291401, title = {Fourth Order Singular Differential Equations.}, journal = {Mathematische Annalen}, volume = {152}, year = {1963}, pages = {320-340}, zbl = {0111.08501}, url = {http://dml.mathdoc.fr/item/GDZPPN002291401} }
EVERITT, W.N. Fourth Order Singular Differential Equations.. Mathematische Annalen, Tome 152 (1963) pp. 320-340. http://gdmltest.u-ga.fr/item/GDZPPN002291401/