@book{67390,
	author = {Dvortsov, E. F. and Polyak, A. Y. and Comisión Económica Europea.},
	title = {High - powered tractors and their implements, including aspects of their impact on the soil},
	publisher = {United Nations,},
	year = {1979},
	series = {AGRI/MECH report},
	address = {New York :}
}