diff --git a/book/state.markdown b/book/state.markdown
index 608b666d..344471ac 100644
--- a/book/state.markdown
+++ b/book/state.markdown
@@ -605,7 +605,7 @@ all this chapter has done is whet your appetite. You'll want to read other books
 to satisfy it.
 
 [behavior trees]: http://web.archive.org/web/20140402204854/http://www.altdevblogaday.com/2011/02/24/introduction-to-behavior-trees/
-[planning systems]: http://web.media.mit.edu/~jorkin/goap.html
+[planning systems]: https://web.archive.org/web/20230412172947/https://alumni.media.mit.edu/~jorkin/goap.html
 
 This doesn't mean finite state machines, pushdown automata, and other simple
 systems aren't useful. They're a good modeling tool for certain kinds of
diff --git a/html/state.html b/html/state.html
index 163c6ae2..088ba72d 100644
--- a/html/state.html
+++ b/html/state.html
@@ -829,7 +829,7 @@ <h2><a href="#pushdown-automata" name="pushdown-automata">Pushdown Automata</a><
 <h2><a href="#so-how-useful-are-they" name="so-how-useful-are-they">So How Useful Are They?</a></h2>
 <p>Even with those common extensions to state machines, they are still pretty
 limited. The trend these days in game AI is more toward exciting things like
-<em><a href="http://web.archive.org/web/20140402204854/http://www.altdevblogaday.com/2011/02/24/introduction-to-behavior-trees/">behavior trees</a></em> and <em><a href="http://web.media.mit.edu/~jorkin/goap.html">planning systems</a></em>. If complex AI is what you&#8217;re interested in,
+<em><a href="http://web.archive.org/web/20140402204854/http://www.altdevblogaday.com/2011/02/24/introduction-to-behavior-trees/">behavior trees</a></em> and <em><a href="https://web.archive.org/web/20230412172947/https://alumni.media.mit.edu/~jorkin/goap.html">planning systems</a></em>. If complex AI is what you&#8217;re interested in,
 all this chapter has done is whet your appetite. You&#8217;ll want to read other books
 to satisfy it.</p>
 <p>This doesn&#8217;t mean finite state machines, pushdown automata, and other simple