Provide a URL to the license that governs the use of the digital resource.
Principle: R
Rationale: Both digital resources and their metadata must be licensed (or equivalent e.g. terms of use, smart contract). The lack of a license indicates that no rights to reuse are granted, thereby detering lawful use. Note that the combination of resources with restrictive license conditions may lead to adverse effects, and ultimately preclude their combined use. To satisfy this metric, two URLs must be provided -> one for the metadata and one for the digital resource.