@article{SF_1994__48_3_135317,
     author = {K.D. jr. Magill},
     title = {More on topological {N-groups.}},
     journal = {Semigroup forum},
     pages = {258--262},
     publisher = {mathdoc},
     volume = {48},
     number = {3},
     year = {1994},
     zbl = {0809.22003},
     url = {http://geodesic.mathdoc.fr/item/SF_1994__48_3_135317/}
}