@incollection{AST_1984__113-114__44_0, author = {Baues, Hans Joachim}, title = { The chains on the loops and $4$-dimensional homotopy types}, booktitle = {Homotopie alg\'ebrique et alg\`ebre locale}, author = {Collectif}, series = {Ast\'erisque}, publisher = {Soci\'et\'e math\'ematique de France}, number = {113-114}, year = {1984}, zbl = {0555.55007}, mrnumber = {749042}, language = {en}, url = {http://www.numdam.org/item/AST_1984__113-114__44_0/} }