About: http://webisa.webdatacommons.org/225200084

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Those pieces such as op. 50 and so on are from later in his career and my guess is that publishers offered him money to make pieces like that and it was a way to make a living so he did it.
http://www.w3.org/ns/prov#wasQuotedFrom	tecla.com