diff --git a/book/external/TeachBooks b/book/external/TeachBooks
index 6fcc3b8..0aaef7a 160000
--- a/book/external/TeachBooks
+++ b/book/external/TeachBooks
@@ -1 +1 @@
-Subproject commit 6fcc3b860e78500d74b14bc5617c2e21ac7981ac
+Subproject commit 0aaef7ab52bb21d42b1a1e37bb9de6bf7c4d3469