Actually a query or Lua would be much better solution for Wikisource instead of sitelinks  (well, author pages can have sitelinks that is no problem).

According to the data model that we have been defining for Wikisource [1] there should be a top-level item (work item) representing all the editions that a text has, then there should be sub-items for each edition (example of a book with several translations [2]). Each one of those sub-items is the one that should be connected with a "sitelink", although there will be only of them per item.

Ideally, the script or the query should examine which items are connected with the property pair "edition/edition of", collect the sitelink of each language and list them all for each one of them.

Is that factible?

Cheers,

Micru

 
[1] https://www.wikidata.org/wiki/Wikidata:Books_task_force
[2] https://www.wikidata.org/wiki/Q6911