[1] Web Annotation Data Model () https://w3c.github.io/web-annotation/model/wd2/#dfn-relationship

Relationship

In the model sections, the term "Relationship" is used to distinguish those features that refer to other Resources, either by reference to the Resource's IRI or by including a description of the Resource in the Annotation's representation. The valid values for a Relationship are: a quoted string containing an IRI, an object that has the "id" property, or an array containing either of these if more than one is allowed.

[2] Selectors and States () https://w3c.github.io/web-annotation/selector-note/#dfn-relationship

Relationship

In the model sections, the term "Relationship" is used to distinguish those features that refer to other Resources, either by reference to the Resource's IRI or by including a description of the Resource in the representation. The valid values for a Relationship are: a quoted string containing an IRI, an object that has the "id" property, or an array containing either of these if more than one is allowed.