Support item source in basic registry item schema

[strogonoff]

Support item sources of two formats:

• Citation. Item was imported either from an unstructured source, such as a book.
• Absolute link. Item was imported from another structured registry.

[ronaldtse]

For citation, please use the model at: https://github.com/relaton/relaton-models

[strogonoff]

Reversing on the idea of two item source formats.

Core registry item schema should support only one source: items imported from another structured registry based on the same format.

Citations could still be provided, but that would be defined by particular register item schema. The reason is that whether citations are used, and in which format, is dependent on particular item class. Some registers will have items that support citations (e.g., ISO GR), while others won’t (e.g., ITU SP).

Register items could use Relaton model for citations, but this would not be in scope of core registry kit.

[ronaldtse]

A citation is technically a relationship, correct? And one can specify multiple of these relationships. Additional “qualifiers” can also be given eg. “identical”, “modified” etc in a relationship.

[strogonoff]

A citation is technically a relationship, correct? And one can specify multiple of these relationships. Additional “qualifiers” can also be given eg. “identical”, “modified” etc in a relationship.

In more complex cases, probably. Looks like different registers may have different ways of specifying citations/information sources (and with different level of detail), part of the reason why I think it should not be dictated by registry framework and will be left up to specific registers.