SOURCE REPOSITORY CITATION

The Source Repository Citation structure is used within a source record to point to the REPOSITORY RECORD, specifying in addition a possible call number or other formal ID of the source within repository.

SOURCE_REPOSITORY_CITATION:=
  n REPO [ @XREF:REPO@ | <NULL>] {1:1}
   +1 <<NOTE_STRUCTURE>> {0:M} 
   +1 CALN <SOURCE_CALL_NUMBER> {0:M} 
    +2 MEDI <SOURCE_MEDIA_TYPE> {0:1}