Multiple URLs for source records

Currently a given reference may optionally include a url key, with a single URL as its value. The idea of a single canonical URL for every resource is somewhat limiting.

Replacing the current key/value url with an array, urls, has the potential to make preservation more adaptable and complete. Example, I don’t subscribe to the New York Times, so when something/someone points me to an article there, I use <archive.is> to view it. So that’s two URLs related to that resource.

The most significant implementation question seems to be whether the new urls key should contain an Array, or a Dict.

A simple array would force meaning into the order of the array, eg. the attribution constructor would have to index from the beginning or the end of the array, taking the first or the last available value. That feels clumsy.

Using a Dict would allow picking URLs on the basis of semantic keys, eg. an <archive.is> URLs could be under archive_is, a Quote Investigator link could be under quote_in OR in a nested references array etc. Would have to explore whether I really want to ‘hardcode’ such sites.