You can find all Johannas CD:s on the Holvi webshop. With or without the signature!
The music book contains compositions for both standard and free bass accordions and some of them are easier, some need a bit more practising.
You can find all the tunes on Johannas albums Miette, Fantasiatango and Fantasiatango 2 and Kraft: Max Höjd. Some of the tunes you can find on Johannas Youtube channel as solo accordion versions.