Js Bach's music is very widely available and so you may surprised to find any here. The Sinfonias (aka "Three-part inventions) although not quite so familiar as the (Two-part) Inventions, can easily be found in libraries, or bought cheaply. But I have never seen them printed in score, - i.e. on three staves, one for each part rather than one for each hand. If you are unused as a player to this arrangement you may find it quite difficult at first to read at the keyboard. It is made a little more difficult here too by the use of the "alto" clef. However if you take the trouble to learn this process - even for just one of these pieces - you wll find that it gives you a new esxperience as you play: you are able to feel the three melodies seperatley and together in a way that is almost impossible if you read from a conventional two-stave score.