@article{MS2_1994__75_2_167302,
     author = {J.H.E. Cohn},
     title = {On {n-Sum} {Groups.}},
     journal = {Mathematica Scandinavica},
     pages = {44--58},
     publisher = {mathdoc},
     volume = {75},
     number = {2},
     year = {1994},
     zbl = {0833.20028},
     url = {http://geodesic.mathdoc.fr/item/MS2_1994__75_2_167302/}
}