@incollection{AST_1977__41-42__35_0, author = {Gras, Georges}, title = {\'Etude d'invariants relatifs aux groupes des classes des corps ab\'eliens}, booktitle = {Journ\'ees arithm\'etiques de Caen}, series = {Ast\'erisque}, pages = {35--53}, publisher = {Soci\'et\'e math\'ematique de France}, number = {41-42}, year = {1977}, mrnumber = {447174}, zbl = {0445.12002}, language = {fr}, url = {http://archive.numdam.org/item/AST_1977__41-42__35_0/} }