diff --git a/doc/developer-notes.md b/doc/developer-notes.md
index 8269d88710..d66562b749 100644
--- a/doc/developer-notes.md
+++ b/doc/developer-notes.md
@@ -104,7 +104,7 @@ Not OK (used plenty in the current source, but not picked up):
 //
 ```
 
-A full list of comment syntaxes picked up by doxygen can be found at http://www.stack.nl/~dimitri/doxygen/manual/docblocks.html,
+A full list of comment syntaxes picked up by doxygen can be found at https://www.doxygen.nl/manual/docblocks.html
 but if possible use one of the above styles.
 
 Development tips and tricks
diff --git a/src/immer/detail/type_traits.hpp b/src/immer/detail/type_traits.hpp
index 091fe04dc2..12bfcdaf6e 100644
--- a/src/immer/detail/type_traits.hpp
+++ b/src/immer/detail/type_traits.hpp
@@ -133,7 +133,7 @@ template <typename T, typename = void>
 struct is_iterator : std::false_type
 {};
 
-// See http://en.cppreference.com/w/cpp/concept/Iterator
+// See https://en.cppreference.com/w/cpp/iterator.html
 template <typename T>
 struct is_iterator<
     T,