@article{GDZPPN002265222, title = {Equivalent Singular Points of Ordinary Linear Differential Equations}, journal = {Mathematische Annalen}, volume = {74}, year = {1913}, pages = {134-139}, zbl = {44.0373.01}, url = {http://dml.mathdoc.fr/item/GDZPPN002265222} }
Birkhoff, G.D. Equivalent Singular Points of Ordinary Linear Differential Equations. Mathematische Annalen, Tome 74 (1913) pp. 134-139. http://gdmltest.u-ga.fr/item/GDZPPN002265222/