@article{MS2_1982__51_166799,
     author = {Ralf Fr\"oberg},
     title = {A study of graded extremal rings and of monominal rings.},
     journal = {Mathematica Scandinavica},
     pages = {22--34},
     publisher = {mathdoc},
     volume = {51},
     year = {1982},
     zbl = {0498.13012},
     url = {http://geodesic.mathdoc.fr/item/MS2_1982__51_166799/}
}