Source: Schema.org v30.1 vocabulary. Official citation property definition.
What does citation mean?
A citation or reference to another creative work, such as another publication, web page, scholarly article, etc.
Used on types (domainIncludes)
Expected value types (rangeIncludes)
Schema.org domainIncludes and rangeIncludes are descriptive guidance, not strict validation prohibitions. Check the official reference for updates.
Related reference
Browse all Schema.org types and properties · Google feature support status