Solutions formelles de systèmes d'équations différentielles ordinaires linéaires homogènes. (Asymptotic solutions of systems of linear ordinary differential equations and fundamental operations for differential operators)

Guoting Chen. Solutions formelles de systèmes d'équations différentielles ordinaires linéaires homogènes. (Asymptotic solutions of systems of linear ordinary differential equations and fundamental operations for differential operators). PhD thesis, Joseph Fourier University, Grenoble, France, 1990. [doi]