diff --git a/book/external/Nested-Books b/book/external/Nested-Books
index c4448a3..d3f9001 160000
--- a/book/external/Nested-Books
+++ b/book/external/Nested-Books
@@ -1 +1 @@
-Subproject commit c4448a3a9f9f5bb81eaa03fe467b98b5b96b403e
+Subproject commit d3f900177406debf040e5c8e6b6945d047444f5d