Hanny - "sheet music" is rarely available for folk songs, although many can be found in collections. Finding a particular song usually means leafing through songbooks in the local folk music store. You could search the 'net for a MIDI file, and I've had some luck asking Mudcatters for a MIDI file of a song I'm interested in (if someone else loves the song and knows the tune they might create one for you), but that means you need the computer software to read it. In one case, someone sent me a gif file I could print directly. So, there are a few options - keep trying but it may take a while.