An important aspect of the I in FAIR is that data or metadata, generally speaking, does not exist in a silo – we must do what is necessary to ensure that the knowledge representing a resource is connected to that of other resources to create a meaningfully interlinked network of data and services. A “qualified reference” is a reference to another resource (i.e., referencing that external resource's persistent identifier), in which the nature of the relationship is also clearly specified.  For instance, when multiple versions of a metadata file are available, it may be useful to provide links to prior or next versions using a named relation such as “prior version” or “next version” (using an appropriate community standard relationship that itself conforms to the FAIR principles). In the case of data, imagine a dataset that specifies the population of cities around the world. To be FAIR with respect to principle I3, the data could contain links to a resource containing city data (e.g., Wikidata [26]), geographical and geospatial data, or other related domain resources that are generated by that city, so long as they are properly qualified references using meaningful, clearly-interpretable relationships. It is also important to note that many different metadata files (containers) being FAIR digital resources in themselves, can be pointing to the same “target” object (a data set or a workflow for instance). For instance a FAIR Digital Object constructed as a nanopublication can have intrinsic metadata (“what is this”) and how was it created (provenance type metadata) as well as “secondary” metadata that are for instance created (separately and later in time) by reusers of a particular digital resource. These could all be metadata containers essentially describing the same digital resource from different perspectives. This principle therefore also relates to the good practice to clearly distinguish between metadata (files/containers) and the resources they describe.

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In the FAIR Implementation Profile (FIP) approach, Principle I3 is addressed through the Semantic Model [A]. A specification that defines qualified relations between entities describing data or other digital objects according to the Linked Data principles. This can include semantic data models and ontologies.

Principle I3 is addressed by a FAIR Supporting Resource type Editor [B], defined as a service that provides a user-friendly interface for easy editing of metadata, vocabularies or crosswalks.

Principle I3 is addressed by a FAIR Supporting Resource type Crosswalk [C], defined as a specification consisting of a set of rules that define how (meta)data elements or attributes from one schema can be aligned and mapped to (meta)data elements or attributes in another schema that share the same constraints and thus share the same semantic role.