item-offering-relation.md

    +-----------------------+
    |  dso:DocumentService  |
    | +------------------+  |   service:providedBy   +------------+
    | | dso:Presentation |  +----------------------->| foaf:Agent |
    | +------------------+  |   service:consumedBy   +------------+
    |                       |
    | +------------------+  |
    | |    dso:Loan      |  |
    | +----------------- +  |    daia:availableFor   +-----------|
    |                       |<-----------------------+ frbr:Item |
    | +------------------+  |   daia:unavailableFor  +-----------+
    | |    dso:...       |  |
    | +----------------- +  |
    +-----------------------+