diff --git a/src/ch15-06-reference-cycles.md b/src/ch15-06-reference-cycles.md
index c828a45d32..a824ec3ea2 100644
--- a/src/ch15-06-reference-cycles.md
+++ b/src/ch15-06-reference-cycles.md
@@ -315,4 +315,4 @@ information.
 Next, we’ll talk about concurrency in Rust. You’ll even learn about a few new
 smart pointers.
 
-[nomicon]: ../nomicon/
+[nomicon]: ../nomicon/index.html
diff --git a/src/ch16-04-extensible-concurrency-sync-and-send.md b/src/ch16-04-extensible-concurrency-sync-and-send.md
index e29e84a239..797f69a991 100644
--- a/src/ch16-04-extensible-concurrency-sync-and-send.md
+++ b/src/ch16-04-extensible-concurrency-sync-and-send.md
@@ -86,4 +86,4 @@ relate to those you might be familiar with from object-oriented programming.
 
 [sharing-a-mutext-between-multiple-threads]:
 ch16-03-shared-state.html#sharing-a-mutext-between-multiple-threads
-[nomicon]: ../nomicon/
+[nomicon]: ../nomicon/index.html