Columbia subject headings:
Harvard subject headings:
Peace (Philosophy)--Congresses.
Peace--Congresses
Peace--Moral and ethical aspects--Congresses.
Peace-building--Congresses
Time--Congresses.
Princeton subject headings:
Peace (Philosophy)--Congresses.
Peace--Congresses.
Peace--Moral and ethical aspects--Congresses.
Peace-building--Congresses.
Time--Congresses.