More on Determinants of Price Elasticity 再谈价格弹性的决定因素
cost / benefit of economizing
   寻找替代品的成本及收益
Expenditure effect (engine oil)
   费用效应(引擎油)
End-benefit effect (Baby and Michelin)
    终端利益效应（米其林和婴儿）
buyer’s prior commitments
   买方是否有事前的投入
separation of buyer and payee
   购买者和付款者的分离