@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},
     address = {Grenoble},
     volume = {23},
     number = {1},
     year = {1973},
     doi = {10.5802/aif.449},
     mrnumber = {49 #10947},
     zbl = {0243.35016},
     language = {fr},
     url = {http://www.numdam.org/articles/10.5802/aif.449/}
}