# 8.6.3.5 IfcDocumentReference

## 8.6.3.5.1 Semantic definition

An IfcDocumentReference is a reference to the location of a document. The reference is given by a system interpretable Location attribute (a URL string) where the document can be found, and an optional inherited internal reference Identification, which refers to a system interpretable position within the document. The optional inherited Name attribute is meant to have meaning for human readers. Optional document metadata can also be captured through reference to IfcDocumentInformation.

## 8.6.3.5.5 Formal representation

ENTITY IfcDocumentReference
SUBTYPE OF (IfcExternalReference);
Description : OPTIONAL IfcText;
ReferencedDocument : OPTIONAL IfcDocumentInformation;
INVERSE
DocumentRefForObjects : SET [0:?] OF IfcRelAssociatesDocument FOR RelatingDocument;
WHERE
WR1 : EXISTS(Name) XOR EXISTS(ReferencedDocument);
END_ENTITY;