@article{MR_1981_23_a20,
     author = {\ensuremath{\Pi}\'{o}\ensuremath{\tau}\ensuremath{\alpha}\ensuremath{\rho}\ensuremath{\eta} \ensuremath{\Delta}\ensuremath{\acute\epsilon}\ensuremath{\sigma}\ensuremath{\pi}o\ensuremath{\iota}\ensuremath{\nu}\ensuremath{\alpha}},
     title = {O\ensuremath{\iota} \ensuremath{\upsilon}\ensuremath{\pi}o\ensuremath{\lambda}o\ensuremath{\gamma}\ensuremath{\iota}\ensuremath{\sigma}\ensuremath{\tau}\ensuremath{\acute\epsilon}\ensuremath{\varsigma} \ensuremath{\sigma}\ensuremath{\tau}\ensuremath{\eta} {\ensuremath{\Delta}\ensuremath{\iota}\ensuremath{\delta}\ensuremath{\alpha}\ensuremath{\sigma}\ensuremath{\kappa}\ensuremath{\alpha}\ensuremath{\lambda}\ensuremath{\acute\iota}\ensuremath{\alpha}} \ensuremath{\tau}\ensuremath{\omega}\ensuremath{\nu} {M\ensuremath{\alpha}\ensuremath{\theta}\ensuremath{\eta}\ensuremath{\mu}\ensuremath{\alpha}\ensuremath{\tau}\ensuremath{\iota}\ensuremath{\kappa}\ensuremath{\acute\omega}\ensuremath{\nu}.}},
     journal = {M\ensuremath{\alpha}\ensuremath{\theta}\ensuremath{\eta}\ensuremath{\mu}\ensuremath{\alpha}\ensuremath{\tau}\ensuremath{\iota}\ensuremath{\kappa}\ensuremath{\acute\eta} E\ensuremath{\pi}\ensuremath{\iota}\ensuremath{\theta}\ensuremath{\varepsilon}\ensuremath{\acute\omega}\ensuremath{\rho}\ensuremath{\eta}\ensuremath{\sigma}\ensuremath{\eta}},
     pages = {67--77},
     year = {1981},
     volume = {23},
     language = {gr},
     url = {http://geodesic.mathdoc.fr/item/MR_1981_23_a20/}
}