@article{MR_2001__56_a9,
     author = {B. N\ensuremath{\tau}\ensuremath{\zeta}\ensuremath{\iota}\ensuremath{\alpha}\ensuremath{\chi}\ensuremath{\rho}\ensuremath{\acute\eta}\ensuremath{\sigma}\ensuremath{\tau}o\ensuremath{\varsigma} and  N. Z\ensuremath{\alpha}\ensuremath{\rho}\ensuremath{\acute\alpha}\ensuremath{\nu}\ensuremath{\eta}\ensuremath{\varsigma}},
     title = {H \ensuremath{\alpha}\ensuremath{\xi}\ensuremath{\iota}o\ensuremath{\pi}o\ensuremath{\acute\iota}\ensuremath{\eta}\ensuremath{\sigma}\ensuremath{\eta} \ensuremath{\tau}\ensuremath{\eta}\ensuremath{\varsigma} \ensuremath{\theta}\ensuremath{\varepsilon}\ensuremath{\omega}\ensuremath{\rho}\ensuremath{\acute\iota}\ensuremath{\alpha}\ensuremath{\varsigma} {Van} {Hiele} \ensuremath{\sigma}\ensuremath{\tau}\ensuremath{\eta}\ensuremath{\nu} \ensuremath{\kappa}\ensuremath{\alpha}\ensuremath{\tau}\ensuremath{\alpha}\ensuremath{\nu}\'{o}\ensuremath{\eta}\ensuremath{\sigma}\ensuremath{\eta} {\ensuremath{\Gamma}\ensuremath{\varepsilon}\ensuremath{\omega}\ensuremath{\mu}\ensuremath{\varepsilon}\ensuremath{\tau}\ensuremath{\rho}\ensuremath{\iota}\ensuremath{\kappa}\ensuremath{\acute\omega}\ensuremath{\nu}} {E\ensuremath{\nu}\ensuremath{\nu}o\ensuremath{\iota}\ensuremath{\acute\omega}\ensuremath{\nu}} \ensuremath{\tau}\ensuremath{\eta}\ensuremath{\varsigma} {A΄} {\ensuremath{\Gamma}\ensuremath{\upsilon}\ensuremath{\mu}\ensuremath{\nu}\ensuremath{\alpha}\ensuremath{\sigma}\ensuremath{\acute\iota}o\ensuremath{\upsilon}} \ensuremath{\mu}\ensuremath{\varepsilon} \ensuremath{\tau}\ensuremath{\eta} \ensuremath{\beta}o\ensuremath{\acute\eta}\ensuremath{\theta}\ensuremath{\varepsilon}\ensuremath{\iota}\ensuremath{\alpha} \ensuremath{\varepsilon}\ensuremath{\kappa}\ensuremath{\pi}\ensuremath{\alpha}\ensuremath{\iota}\ensuremath{\delta}\ensuremath{\varepsilon}\ensuremath{\upsilon}\ensuremath{\tau}\ensuremath{\iota}\ensuremath{\kappa}o\ensuremath{\acute\upsilon} {\ensuremath{\Lambda}o\ensuremath{\gamma}o\ensuremath{\sigma}\ensuremath{\mu}\ensuremath{\iota}\ensuremath{\kappa}o\ensuremath{\acute\upsilon}.}},
     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 = {55-74},
     publisher = {mathdoc},
     volume = {56},
     year = {2001},
     language = {gr},
     url = {http://geodesic.mathdoc.fr/item/MR_2001__56_a9/}
}