Licensing advice

[Barry Norton]

I'd like to publicly release R2RML mappings for the MusicBrainz dataset. 
DBpedia has shown interest in including the subset that can be used to 
create a linkset.

Any idea what (kind of) licence could/should apply? (To be clear, to the 
mappings, as opposed to the dataset)

I'd also like to attach, since R2RML is RDF, a licence and attribution 
on a per rr:TriplesMap basis. (The mappings are hosted on github and 
contributions will be accepted as I'm never going to get through all of 
the MB Advanced Relationships, a moving target, myself and I'm being a 
bottleneck.)

The question's also been raised on whether a given licence can in turn 
impose conditions on the triples that are created using it (as 
derivative works)? Does that sound feasible?

Any input appreciated.

Barry