manifestation_id	A unique ID number assigned to each manifestation in the database.
area_location_id	A unique ID number assigned to specific locations. The area_location table holds the numbers and the associated places.
repository_owner_id	A unique ID number assigned to a repository in the repository table.
source_manifestation_id	A unique ID number assigned to the source of each manifestation. They are kept in the source_manifestation table.
work_id	A unique ID number assigned to each work and kept in the work table.