@article{IM_1973__21_142228,
     author = {Graeme Segal},
     title = {Configuration-Spaces and {Iterated} {Loop-Spaces.}},
     journal = {Inventiones mathematicae},
     pages = {213--222},
     year = {1973},
     volume = {21},
     zbl = {0267.55020},
     url = {http://geodesic.mathdoc.fr/item/IM_1973__21_142228/}
}