@article{MZ_1971__119_171484,
     author = {Roger M. Bryant},
     title = {On {Join} {Varieties} of {Groups.}},
     journal = {Mathematische Zeitschrift},
     pages = {143--148},
     publisher = {mathdoc},
     volume = {119},
     year = {1971},
     zbl = {0198.04201},
     url = {http://geodesic.mathdoc.fr/item/MZ_1971__119_171484/}
}