@article{MR_1981_21_a20,
     author = {\ensuremath{\Delta}. \ensuremath{\Pi}\'{o}\ensuremath{\tau}\ensuremath{\alpha}\ensuremath{\rho}\ensuremath{\eta}},
     title = {\ensuremath{\Delta}\ensuremath{\upsilon}\ensuremath{\sigma}\ensuremath{\kappa}o\ensuremath{\lambda}\ensuremath{\acute\iota}\ensuremath{\varepsilon}\ensuremath{\varsigma} {M\ensuremath{\acute\alpha}\ensuremath{\theta}\ensuremath{\eta}\ensuremath{\sigma}\ensuremath{\eta}\ensuremath{\varsigma}} \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}} \ensuremath{\sigma}\ensuremath{\tau}o {\ensuremath{\Delta}\ensuremath{\eta}\ensuremath{\mu}o\ensuremath{\tau}\ensuremath{\iota}\ensuremath{\kappa}\'{o}} {\ensuremath{\Sigma}\ensuremath{\chi}o\ensuremath{\lambda}\ensuremath{\varepsilon}\ensuremath{\acute\iota}o.}},
     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 = {3--22},
     year = {1981},
     volume = {21},
     language = {gr},
     url = {http://geodesic.mathdoc.fr/item/MR_1981_21_a20/}
}