@article{MR_1996_45_a8,
     author = {Kiriakie Kiriaki and  Zoi Rapti},
     title = {An {Extrerior} {Mixed} {Boundary} {Value} {Problem} for the {Helmholtz} {Equation}},
     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 = {43--55},
     year = {1996},
     volume = {45},
     language = {gr},
     url = {http://geodesic.mathdoc.fr/item/MR_1996_45_a8/}
}