00409nam a2200157Ia 4500008004100000020001500041082001600056100002400072245005000096260002600146300000800172650001400180650002000194653001600214653002100230170901s1977    xx            000 0 und d  a0246113898  a338.1bR54A  aRitson, Christopher 0aAgricultural EconomicsbPrinciples and Policy  aLondonbGranadac1977  a409  aEconomics  aSocial sciences  aAgriculture  aEconomic aspects