@article{EUG_1993__38_a20,
     author = {Constantinos N. Yatras},
     title = {Characteristic of {M-polysymmetrical} {Hyperrings} and some properties of {M-Polysymmetrical} {Hyperrings} with {Unity}},
     journal = {E\ensuremath{\upsilon}\ensuremath{\kappa}\ensuremath{\lambda}\ensuremath{\varepsilon}\ensuremath{\acute\iota}\ensuremath{\delta}\ensuremath{\eta}\ensuremath{\varsigma} \ensuremath{\Gamma}
},
     pages = {115-125},
     publisher = {mathdoc},
     volume = {38},
     year = {1993},
     language = {gr},
     url = {http://geodesic.mathdoc.fr/item/EUG_1993__38_a20/}
}