Thanks, guest - I found it and will work on it. Thanks also Joe for your thoughts.
My problem is that I'm living in Italy, and the "music police" (SIAE) here, the copyright collecting organization, make the "equivalents" in most other countries look like tame mice. Somebody gets out their banjo and plays a handful of songs at a birthday party in a community hall - that will be 150 Euros, please. No matter that it was a private party where nobody paid and nobody got paid. The worst of it is that, with the songs being unattributable (who wrote the Young Sailor Cut Down, or for that matter the House of the Rising Sun) the money mostly goes to the organization's pockets, and a bit of it goes to their favourites - TV cabaret singers and the like.
So essentially I'm looking to be able to say: these are part of the creative commons. We are not copying any one particular prior recording, but drawing on a broad, old, mix of ideas and traditions. Therefore we do not need to pay.
Yes, it's a can of worms.