Article evaluation edit

This is an article review for zero-sum game on Wikipedia. Everything in this article is closely related to the topic and it’s written from a neutral point of view. The content is fair and has no editorial bias.
However, I was distracted by the external link after reading the third sentence since I was confused at that moment. The link directed me to the related topic – marginal utility. After I checked the Talk page, I noticed that another Wiki user found it confusing as well.
After checking on the references, I found out that one of the links that comes from Princeton University Press is not working. It was retrieved on 11/11/2010, which is 8 years ago. My suggestion is that Wiki editors should check the reference lists more frequently in order to have up-to-date information in the content. Dorisdd (talk) 03:44, 15 February 2018 (UTC)