Penguin Classics on Wikisource

As a way of learning Sparql and more about Wikidata, I’m trying to make a list of which pre-1924 Penguin Classics are on Wikisource.

Penguin lists their books at penguin.com.au/browse/by-imprint/penguin-classics.

The following Wikidata Query Service query lists all editions published by Penguin, their date of original publication, and whether there’s an Index page on Wikisource for the work or edition.

SELECT ?edition ?editionLabel ?work ?workLabel ?originalPublicationDate ?wikisourceIndexForWork ?wikisourceIndexForEdition
WHERE
{
  ?edition wdt:P31 wd:Q3331189 .
  ?edition wdt:P577 ?publicationDate .
  ?edition wdt:P123 ?publisher .
  FILTER(
    ?publisher = wd:Q1336200 # Penguin Books Q1336200
    || ?publisher = wd:Q11281443 # Penguin Classics Q11281443
  )
  ?edition wdt:P629 ?work .
  OPTIONAL{ ?work wdt:P577 ?originalPublicationDate } .
  OPTIONAL{ ?work wdt:P1957 ?wikisourceIndexForWork } .
  OPTIONAL{ ?edition wdt:P1957 ?wikisourceIndexForEdition } .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en" }
}

I’m not sure how often the WDS data is updated, but so far it’s not being very useful for on-the-fly checking of recent updates. I’m sure there’s a better way of doing that though.