@article{AM2_1968__1_135981,
     author = {Kermit Sigmon},
     title = {Medial {Topological} {Groupoids.} {(Short} {Communication).}},
     journal = {Aequationes mathematicae},
     pages = {306--307},
     publisher = {mathdoc},
     volume = {1},
     year = {1968},
     url = {http://geodesic.mathdoc.fr/item/AM2_1968__1_135981/}
}