I add references to broadsides, where relevant, and I think it would be a good idea; the Bodleian site is consistent and (so far) even links from a couple of years back still work. They don't mind you doing it (if I've understood their coyright page correctly), though I usually add a link to their home page, too, as a courtesy and to help people who are new to it.

Tunes: one of the problems with the DT at present is that some files have more than one tune, often with no clear indication as to which belongs to the text given. When adding tunes, I'd suggest that we stick to those which we know belong to texts which we have, except where we have texts the tunes for which were not noted.

When tracing "missing" tunes, I've sometimes provided English or Irish variants for songs collected in Canada, for example, but only where no tune was recorded in the book from which the DT text was taken and I can't find a close regional variant that does have music. I try always to be very precise about where it came from, and to state clearly that, though the tune may be close to the one actually used, there is no evidence that it actually is.