Deere, John Operator's manual : 4050 (006510) 4250 (009673) 4450 (019805) tractors / John Deere. - [s.l] : [s.e], [s.f]. - 348 p. aprox. : il. ; - John Deere Tractor Work's . Incluye índice. Dewey Class. No.: R631.372 / D22o