Hi Dario,

Thanks for your proposal and starting the discussion. I'm skeptical about any items that refer to internal aspects of Wikidata so I wonder whether we actually need a rather artificial class such as "Wikidata item collection". You wrote:

> 2. create and document individual collections (e.g. the Wikidata Zika corpus [Q-Y]) as instances of this class: [Q-Y] --P31--> [Q-X]

> 3. add appropriate metadata to describe such collections (its main topic(s), creators, any external identifiers, if applicable)

> 4. mark individual bibliographic items as part of [P361] the corresponding collections

We already have several classes for collections, e.g. bibliography (Q134995) or bibliographic database (Q1789476), what's wrong or missing when using them? The Zika corpus is a bibliography. We also have a large number of other bibliographic databases that might get imported into Wikidata, e.g. PubMed that can be linked to bibliographic items in the same way.

> Some criteria would be needed to determine an appropriate threshold for legitimate

> collections (we wouldn't want arbitrary collections to be created for sets of items generated as part of a test import).

That's the more important question. There should be at least a WikiProject page about the collection and I'd classifiy such projects as bibliographies or other kinds of catalogs.

> If something similar already exists in the context of structured data donations/imports for GLAM, I'd be most grateful for any pointers.

See property catalog code (P528) and its use e.g. at Mona Lisa (Q12418).

Jakob

P.S: At the moment we have 9275 instances of catalog (Q2352616) or its subclasses.