<Ul> <Li> http://www.econlib.org/library/Marshall/marP12.html <Dl> <Dd> Triggered by \ beconlib \. org \ b on the local blacklist </Dd> </Dl> </Li> </Ul> <Li> http://www.econlib.org/library/Marshall/marP12.html <Dl> <Dd> Triggered by \ beconlib \. org \ b on the local blacklist </Dd> </Dl> </Li> <Dl> <Dd> Triggered by \ beconlib \. org \ b on the local blacklist </Dd> </Dl> <Dd> Triggered by \ beconlib \. org \ b on the local blacklist </Dd>

Based on the concept of price elasticity of demand