 Genée, however, wrote the operetta's actual text and drew nothing from Haffner beyond the names of the characters.One of his best-known works was the libretto of Karl Millöcker's operetta "Der Bettelstudent", which he co-wrote with Friedrich Zell (the pseudonym of Camillo Walzel).He also wrote the libretto to Ella Adayevskaya's 1877 opera "Zarya".