Columbia subject headings:
Composers' spouses--Korea (South)--Correspondence.
Composers--Germany (West)--Correspondence.
Composers--Korea (South)--Correspondence.
Personal correspondence.
Yi, Su-ja, 1927---Correspondence.
Yun, Isang--Correspondence.
Harvard subject headings:
Composers--Korea (South)--Correspondence.
Personal correspondence
Yun, Isang--Correspondence.
Princeton subject headings:
Composers--Korea--Correspondence.
Personal correspondence.
Yun, Isang--Correspondence.