@article{DEME_1979_20_a13,
     author = {E. C. Zachmanoglou},
     title = {Solutions which are flat or {Singular} on {Totally} {Characteristic} {Manifolds} of first order {Partial} {Differential} {Equations} },
     journal = {\ensuremath{\Delta}\ensuremath{\varepsilon}\ensuremath{\lambda}\ensuremath{\tau}\ensuremath{\acute\iota}o \ensuremath{\tau}\ensuremath{\eta}\ensuremath{\varsigma} E\ensuremath{\lambda}\ensuremath{\lambda}\ensuremath{\eta}\ensuremath{\nu}\ensuremath{\iota}\ensuremath{\kappa}\ensuremath{\acute\eta}\ensuremath{\varsigma} M\ensuremath{\alpha}\ensuremath{\theta}\ensuremath{\eta}\ensuremath{\mu}\ensuremath{\alpha}\ensuremath{\tau}\ensuremath{\iota}\ensuremath{\kappa}\ensuremath{\acute\eta}\ensuremath{\varsigma} E\ensuremath{\tau}\ensuremath{\alpha}\ensuremath{\iota}\ensuremath{\rho}\ensuremath{\acute\iota}\ensuremath{\alpha}\ensuremath{\varsigma}},
     pages = {149--158},
     year = {1979},
     volume = {20},
     language = {gr},
     url = {http://geodesic.mathdoc.fr/item/DEME_1979_20_a13/}
}