Update README.md

snrazavi · web-flow · commit 65cf999e7578 · 2021-10-01T02:43:02.000+01:00
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 # AI-Programming-using-Python
-This repository contains implementation of different AI algorithms, based on the amazing AI book [Artificial Intelligence: A Modern Approach](http://aima.cs.berkeley.edu).
+This repository contains implementation of different AI algorithms, based on the amazing AI book [Artificial Intelligence: A Modern Approach](http://aima.cs.berkeley.edu) (4th edition, 2020).
 ## Contents
 
 ### First part:
