References

References

OpenAtlas uses P67 (“refers to”) in order to link various entities to references. References can be:

  • Documents (E31) such as files, bibliographic entities, or references like URLs, DOIs, etc.

  • Linguistic Objects (E33) such as the content of a medieval charter

In order to record which part of the document contains the respective reference a delimiter respectively a certain value to determine the position in the reference, is stored along with the link between the entities. This can be a page numbers of a book, a chapter, a figure number, etc.

../_images/references.png 
E31(Document) - P67(refers to) - E21(Person) at delimiter: "Folio 7v"

Example: [Book of Kells (E31 Document)] refers to (P67) [Saint Mary (21 Person)] at delimiter: “Folio 7v”

Each reference document is more or less unique and can refer to multiple entities. The distinction is defined by the delimiter value. If the document as a whole refers to the entity, no delimiter is necessary.

Reference Systems

Reference systems include sources such as vocabularies, gazetteers, etc. They are considered authority documents (E32).

Users can define a reference system by defining a name, class, and description.

Example:

  • Name: GeoNames

  • Class: E32

  • Description: GeoNames - a geographical database - contains geographical information on all countries and the dataset includes over eleven million place names that are available for download free of charge.

OpenAtlas distinguishes between:

  • Functional web resources, implemented via an API, etc.

  • Non-digital/non-web-functional resources such as printed encyclopedia, card catalogs, inventory records, etc.

The link between an entity and the Authority Document is stored in the model.link table in the following way:

  • domain_id: ID of the Authority Document

  • property_code: P67

  • range_id: ID of the entity

  • description: delimiter (alphanumerical)

This combination of E32 and delimiter can be resolved as E31 Document as it is a unique reference documenting the entity while the E32 by itself can be considered as container for all possible references from this authority document.

../_images/reference_system.png 
E21(Person) - P67i(is referred to by) - E31(Document) - P71(is listed in) -
E32(Authority Document)

Example: [Terry Prattchet (21 Person)] is referred to by (P67i) [Q46248 (E31 Document)] is listed in (P71i)[WikiData (E32)]

For more information on reference systems see the following links: References Systems and Reference System.

References and Files

Various entities can be connected to files. This is mapped as:

E31 (Document = file) - refers to (P67) - E1

Files can refer to any of the “top level” entities and can be (but don’t have to be) images. Files are stored with a certain system type (i.e. file). If the file is an image, this is most probably a depiction of the entity.

A file can be linked to a reference, such as a bibliographical reference to the publication the file originates from. In this creates a link between a document E31 and a type “Bibliography” via P67 to another document E31 with a system type “file”. In this case the file is not the depiction of the reference but the reference is the origin of the file. This is mostly needed to document the copyright respectively right holder or source of a file.