Wikidata property values are effectively retrieved by #property inclusion syntax, but it work only when used into the wikisource page directly linked to a wikidata element.
An effective management of a "book" (best, a literary work) needs creation of two different elements ("work" and "edition"); ns0 wikisource pages can be linked to "edition" wikidata element just as Author: pages are linked to author's wikidata element; on the contrary, presently there's no wikisource page that could be linked to "work" wikidata element, so the data of the latter can't be retrieved into wikisource by #property inclusion syntax.
I'm testing a strange idea: to create wikisource "work" pages as subpages of author's page. It seems a nonsense location, but it has a long series of advantages and few disadvantages IMHO:
* omonimies decrease sharply; * there's a logical and implicit link between author and his works; * work pages can be very simply self-categorized as [[Category:Works by {{BASEPAGENAME}}]] * joining {{#property:...}} and {{subst:#property:...}} codes, such work pages both show data and run as templates to access the data from any other page. * the code can be completely standardized and can be easily created/updated by bot, simply posting the same base code into any work page, new or old.
Tests are going on working using https://it.wikisource.org/wiki/Autore:Silvio_Pellico and its related wikidata elements.
Alex brollo