Obrecht, Jacob Ockeghem, Johannes Offenbach, Jacques Ónozó János Orbán György Oromszegi Ottó Országh Tivadar Ortiz, Diego Ott Rezső Ónozó János (edited by) Orbán György (composer-contributor) Orbán György (edited by) Orbán György (arranged by) Orbán György (transcribed by) Orbán György (edited by) Orbán György (piano score by) Orbán Ottó (translated by) Ormay Imre (translated by) Ormay Imre (words by) Oromszegi Ottó (edited by) Országh Tivadar (transcribed by) Országh Tivadar (transcribed for violin and piano) Országh Tivadar (compiled by) Ortega, J. (edited by) Ortega, J. (transcribed and edited by) Osvát Erzsébet (words by) Ott Rezső (piano score by)