@article{AIF_1973__23_1_157_0, author = {G\'erard, R. and Levelt, A. M.}, title = {Invariants mesurant l'irr\'egularit\'e en un point singulier des syst\`emes d'\'equations diff\'erentielles lin\'eaires}, journal = {Annales de l'Institut Fourier}, pages = {157--195}, publisher = {Institut Fourier}, volume = {23}, number = {1}, year = {1973}, doi = {10.5802/aif.449}, zbl = {0243.35016}, mrnumber = {49 #10947}, language = {fr}, url = {http://archive.numdam.org/articles/10.5802/aif.449/} }