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Interrelationships between spatial variability and levels of national grain productivity in the USSR, 1955-1974
Berentsen, William H., (1985)
Razvitie zernovogo chozjajstva
Bystrakov, Jurij Ivanovič, (1983)
ZMP-Bilanz / Getreide, Ölsaaten, Futtermittel
(1999)