@article{MAN_1979__239_163202,
     author = {R. Rousseau and A. van Daele},
     title = {Crossed {Products} of {Communtation} {Systems.}},
     journal = {Mathematische Annalen},
     pages = {7--20},
     publisher = {mathdoc},
     volume = {239},
     year = {1979},
     zbl = {0389.46046},
     url = {http://geodesic.mathdoc.fr/item/MAN_1979__239_163202/}
}