Columbia subject headings:
Agricultural innovations--Russia--History--Congresses.
Agriculture--Russia (Federation)--History--Congresses.
Agriculture--Russia--History--Congresses.
Agriculture--Soviet Union--History--Congresses.
Harvard subject headings:
Agricultural innovations--Russia--History--Congresses.
Agriculture--Russia (Federation)--History--Congresses.
Agriculture--Russia--History--Congresses.
Agriculture--Soviet Union--History--Congresses.
Princeton subject headings: