Provide field to reference source dataset(s) a dataset was derived from

[philipashlock]

To trace the provenance of dataset that was derived from other datasets a field should be provided to reference source datasets.

As originally discussed in #258 (comment) I would recommend the Dublin Core source property referencing the identifier of the source. Dublin Core defines it as:

The described resource may be derived from the related resource in whole or in part. Recommended best practice is to identify the related resource by means of a string conforming to a formal identification system.

[mhogeweg]

👍 One thing to discuss is if the reference is to another item in the DCAT listing or to the actual resource elsewhere.

[rebeccawilliams]

See also metadata_sources as suggested in #308