Essentials of Economics

Krugman, Paul; Wells, Robin

4th ed.

New York: Worth Publishers, Macmillan Learning, 2017

p. 272

A strategy of tit for tat involves playing cooperatively at first, then doing whatever the other player did in the previous period.

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p. 128

In response, marine biologists set a total catch quota system, which limited the amount of crab that could be harvested annually in order to allow the crab population to return to a healthy, sustainable level.

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