diff --git a/book/external/TeachBooks b/book/external/TeachBooks
index eb5f90c..0cfcaed 160000
--- a/book/external/TeachBooks
+++ b/book/external/TeachBooks
@@ -1 +1 @@
-Subproject commit eb5f90c86e6f9dd368c513b2d958f77fb941cae0
+Subproject commit 0cfcaeda19fc510a62667dec1ef891e4bbc757e3