In any API with multiple resource types, it’s likely that there will be a need for resources to point at one another. Though this manner of referencing resources may appear trivial, many of the behavioral details are left open for interpretation, which means there is the opportunity for inconsistency. This pattern aims to clarify how these references should be defined and, more importantly, how they should behave.
Resources rarely live in a vacuum. As a result, there must be a way for resources to reference one another. These references range from the local (e.g., other resources in the same API) to the global (e.g., resources that live elsewhere on the wider internet) and may fall in between as well (e.g., resources in a different API offered by the same provider) (figure 13.1).
