@article{MR_1984_28_a3,
     author = {Pavlos Sinopoulos},
     title = {A {New} {Generalization} of {Sine} and cosine functional equations},
     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--49},
     year = {1984},
     volume = {28},
     language = {gr},
     url = {http://geodesic.mathdoc.fr/item/MR_1984_28_a3/}
}