@article{10_4153_CMB_1973_007_2,
     author = {Biggs, R. G.},
     title = {On the {Central} {Series} of a {Ring}},
     journal = {Canadian mathematical bulletin},
     pages = {27--32},
     year = {1973},
     volume = {16},
     number = {1},
     doi = {10.4153/CMB-1973-007-2},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1973-007-2/}
}