@misc{Schubert_Franz_(1797-1828}_Impromptu,
 author={Schubert, Franz (1797-1828}},
 howpublished={online},
 publisher={Idzikowski Leon},
 language={fre},
 type={druk muzyczny},
 title={Impromptu As-dur : op.90 nr 4 : [pour piano]},
}