@book{ 0-1358197822, title = {25 leichte Etüden für Klavier op. 100}, author = {Bertini, Henri and Ruthardt, Adolf}, editor = {Ruthardt, Adolf}, address = {Leipzig}, publisher = {Peters}, year = {1971}, language = {Undetermined}, url = {https://katalog.hmt-leipzig.de/Record/0-1358197822} }