https://neo4j.com/labs/apoc/4.2/graph-querying/relationship-querying/
Relationship Querying - APOC Extended Documentation
This section describes procedures that can be used to query relationships.
relationship queryingapoc extendeddocumentation
https://www.mail-archive.com/search?l=wikidata-l@lists.wikimedia.org&q=subject:%22Re%5C%3A+%5C%5BWikidata%5C-l%5C%5D+querying+wikidata+for+an+unknown+relationship+between+two+items%22&o=newest&f=1
subject:"Re\: \[Wikidata\-l\] querying wikidata for an unknown relationship between two items"
for an
https://plone.org/news-and-events/events/plone-conferences/naples-2007/speakers/sessions/relationship-building-defining-and-querying-complex-relationships-between-your-content
Relationship Building: Defining and querying complex relationships between your content
relationship buildingdefiningqueryingcomplexrelationships