Internal search

[LauraErhard]

My current reference is a book chapter. The chapter and the edited book are both in the SWB. Therefore I just searched for the edited book and migrated it. Then I searched for the chapter and migrated that too, then I wanted to use the link to existing container to bring them together. But I can't find the edited book again. I tried everything but it doesn't show up. The link to existing container doesn't list it and I can't find it via browse either (I checked the all resources json to be sure I really migrated it and there it is listed).
While trying all this out, I noticed that we can search with the SWB PPN & ISBN only in the external sources. Could you make both search options possible for the internal suggestions/browse feature/link to existing container search as well? Then I could just search with one of these identifiers and hopefully get a better result.

Edit: If it helps, the resource I can't find is: Achsen der Ungleichheit : zum Verhältnis von Klasse, Geschlecht und Ethnizität / Cornelia Klinger - ID: 5c0a610c2c151d0d2d679584

[LauraErhard]

Can you make the internal ID searchable as well? We noticed that a few articles from the same issue aren't linked to the same parent and it would be the easiest way to switch them to the same container via internal ID.
If it's not that time-consuming it would be nice to just be able to search with all identifiers we have at our disposal.