Secondary markets with changing preferences
研究了消费者偏好随时间变化时，二级市场摩擦可能提高垄断利润并导致耐用性偏离成本最小化水平，并利用图书市场数据提供了证据。
If consumer valuations change over time, then secondary‐market frictions may raise monopoly profits and cause durability to be distorted away from the cost‐minimizing level. A monopolist who favors such frictions overinvests in durability, but planned obsolescence instead may be preferred when market frictions exist but a monopolist wishes they did not. Evidence from the book market is presented.