@article{PDML_1976__13_4_27_0,
     author = {Cenkl, Bohumil},
     title = {Iterated {Integrals} and {Homotopy} {Periods}},
     journal = {Publications du D\'epartement de math\'ematiques (Lyon)},
     pages = {27--71},
     publisher = {Universit\'e Claude Bernard - Lyon 1},
     volume = {13},
     number = {4},
     year = {1976},
     mrnumber = {478141},
     zbl = {0407.58002},
     language = {en},
     url = {http://archive.numdam.org/item/PDML_1976__13_4_27_0/}
}