Groupes algébriques et équations différentielles linéaires
Séminaire Bourbaki : années 1948/49 - 1949/50 - 1950/51, exposés 1-49, Séminaire Bourbaki, no. 1 (1952), Talk no. 17, p. 103-109 
@incollection{SB_1948-1951__1__103_0,
     author = {Blanchard, Andr\'e},
     title = {Groupes alg\'ebriques et \'equations diff\'erentielles lin\'eaires},
     booktitle = {S\'eminaire Bourbaki : ann\'ees 1948/49 - 1949/50 - 1950/51, expos\'es 1-49},
     author = {Collectif},
     series = {S\'eminaire Bourbaki},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {1},
     year = {1952},
     note = {talk:17},
     pages = {103-109},
     mrnumber = {1605133},
     language = {fr},
     url = {http://www.numdam.org/item/SB_1948-1951__1__103_0}
}

Blanchard, André. Groupes algébriques et équations différentielles linéaires, in Séminaire Bourbaki : années 1948/49 - 1949/50 - 1950/51, exposés 1-49, Séminaire Bourbaki, no. 1 (1952), Talk no. 17, pp. 103-109. http://www.numdam.org/item/SB_1948-1951__1__103_0/

[1] Kolchin (E.R.). - Algebraic groupa and the Picard-Vessiot theory of homogeneous linear ordinary differential equations, Annals of Math., t. 49, 1948, p. 1-42. | MR 24884 | Zbl 0037.18701

[2] Kolchin (E.R.). - Galois theory of differential fields, Amer. J. Math., t. 75, 1953, p. 753-824. | MR 58591 | Zbl 0052.27301

[3] Kolchin (E.R. ). - On the theory of differentiable fields, Amer. J. Math., t. 77, 1955, p. 868-894. | MR 73588 | Zbl 0067.27004