@incollection{AST_2009__323__61_0,
     author = {Cano, Jos\'e and Fortuny Ayuso, Pedro},
     title = {The space of generalized formal power series solution of an ordinary differential equation},
     booktitle = {\'Equations diff\'erentielles et singularit\'es. En l'honneur de J. M. Aroca},
     editor = {Cano F. and Loray F. and Moralez-Ruiz J. J. and Sad P. and Spivakovsky M.},
     series = {Ast\'erisque},
     pages = {61--81},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {323},
     year = {2009},
     zbl = {1272.34015},
     language = {en},
     url = {http://www.numdam.org/item/AST_2009__323__61_0/}
}