7Fallak S S, Sverker P E E Vacuum nozzle design for Seed metering[J]. Transactions of the ASAE, 1984, 27(3): 688-696.
8Shafi S, Holmes R G. Air-jet seed metering a theoretical and experimental study[J]. Transactions of the ASAE, 1990, 33(5): 1432-1438.
9Guarella P, Pellerano A, Pascuzzi S, Experimental and theoretical performance of a vacuum seeder nozzle for vegetable seeds[J]. J Agric Engng Res, 1996, 64: 29-36.