Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{MAN_1970__187_162005, author = {Juan Jorge Sch\"affer}, title = {Linear {Difference} {Equations:} {Closedness} of {Covariant} {Sequences.}}, journal = {Mathematische Annalen}, pages = {69--76}, publisher = {mathdoc}, volume = {187}, year = {1970}, zbl = {0185.22501}, url = {http://geodesic.mathdoc.fr/item/MAN_1970__187_162005/} }
Juan Jorge Schäffer. Linear Difference Equations: Closedness of Covariant Sequences.. Mathematische Annalen, Tome 187 (1970), pp. 69-76. http://geodesic.mathdoc.fr/item/MAN_1970__187_162005/