@article{EUG_1990_25_a18,
     author = {\ensuremath{\Pi}\'{o}\ensuremath{\lambda}. \ensuremath{\Sigma}\ensuremath{\acute\iota}\ensuremath{\delta}\ensuremath{\varepsilon}\ensuremath{\rho}\ensuremath{\eta}\ensuremath{\varsigma}},
     title = {\ensuremath{\Gamma}\ensuremath{\varepsilon}\ensuremath{\omega}\ensuremath{\mu}\ensuremath{\varepsilon}\ensuremath{\tau}\ensuremath{\rho}\ensuremath{\iota}\ensuremath{\kappa}\ensuremath{\acute\eta} {\ensuremath{\Pi}\ensuremath{\rho}o\ensuremath{\sigma}\ensuremath{\acute\epsilon}\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\iota}\ensuremath{\sigma}\ensuremath{\eta}} \ensuremath{\tau}\ensuremath{\omega}\ensuremath{\nu} {I\ensuremath{\delta}\ensuremath{\iota}o\ensuremath{\tau}\ensuremath{\acute\eta}\ensuremath{\tau}\ensuremath{\omega}\ensuremath{\nu}} \ensuremath{\tau}\ensuremath{\eta}\ensuremath{\varsigma} {\ensuremath{\Lambda}o\ensuremath{\gamma}\ensuremath{\alpha}\ensuremath{\rho}\ensuremath{\iota}\ensuremath{\theta}\ensuremath{\mu}\ensuremath{\iota}\ensuremath{\kappa}\ensuremath{\acute\eta}\ensuremath{\varsigma}} \ensuremath{\mu}\ensuremath{\varepsilon} \ensuremath{\alpha}\ensuremath{\varphi}\ensuremath{\varepsilon}\ensuremath{\tau}\ensuremath{\eta}\ensuremath{\rho}\ensuremath{\acute\iota}\ensuremath{\alpha} \ensuremath{\mu}\ensuremath{\iota}\ensuremath{\alpha} {\ensuremath{\sigma}\ensuremath{\upsilon}\ensuremath{\nu}\ensuremath{\acute\alpha}\ensuremath{\rho}\ensuremath{\tau}\ensuremath{\eta}\ensuremath{\sigma}\ensuremath{\eta}-O\ensuremath{\lambda}o\ensuremath{\kappa}\ensuremath{\lambda}\ensuremath{\acute\eta}\ensuremath{\rho}\ensuremath{\omega}\ensuremath{\mu}\ensuremath{\alpha}}},
     journal = {E\ensuremath{\upsilon}\ensuremath{\kappa}\ensuremath{\lambda}\ensuremath{\varepsilon}\ensuremath{\acute\iota}\ensuremath{\delta}\ensuremath{\eta}\ensuremath{\varsigma} \ensuremath{\Gamma}},
     pages = {21--26},
     year = {1990},
     volume = {25},
     language = {gr},
     url = {http://geodesic.mathdoc.fr/item/EUG_1990_25_a18/}
}