Subfield code $1 - Real World Object URI (Appendix A: Control Subfields)
Subfield $1 contains a URI that identifies a description of an entity, sometimes referred to as a Thing, a Real World Object or RWO, whether actual or conceptual. When dereferenced, the URI points to a description of that entity. A URI that identifies a name or label for an entity is contained in $0.
Examples:
100 1# $aObama, Michelle,$d1964-$0http://id.loc.gov/authorities/names/n2008054754$1http://viaf.org/viaf/81404344
100 1# $aSanta Claus$0http://id.loc.gov/authorities/names/no2015039717$1http://dbpedia.org/resource/Santa_Claus
700 1# $aJemison, Mae,$d1965-$0http://id.loc.gov/authorities/names/n95004729$1http://id.loc.gov/rwo/agents/n95004729
See also: