Monodromy preserving deformation of linear ordinary differential equations with rational coefficients, I,- General theory and $\tau- \mathrm{f}\mathrm{u}\mathrm{n}\mathrm{c}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}-$, Phusica 2D (1981)

by M Jimbo, T and K Ueno Miwa