There seems to be some confusion about the opus number of "Capriccio sopra un tema della Niobe di Pacini". This disc references it as op 21. However, other cds reference it as op 22. Having listened to this track and also to the excerpt at http://www.allmusic.com/album/alfredo-piatti-cappricci-per-violoncello-solo-op-22-e-op-25-mw0001400806 they appear to be the same work. I've assumed they are the same and that this CD has it wrong, so I've linked the recording to the op. 22 work.