diff --git a/c++/itertools/iterator_facade.hpp b/c++/itertools/iterator_facade.hpp
index 371ba63..acc894a 100644
--- a/c++/itertools/iterator_facade.hpp
+++ b/c++/itertools/iterator_facade.hpp
@@ -60,10 +60,10 @@ namespace itertools {
   template <typename Iter, typename Value, typename Reference, typename Difference>
   struct iterator_facade<Iter, Value, std::forward_iterator_tag, Reference, Difference> {
     private:
-    /// Get a reference to the derived iterator.
+    // Get a reference to the derived iterator.
     [[nodiscard]] Iter &self() { return static_cast<Iter &>(*this); }
 
-    /// Get a const reference to the derived iterator.
+    // Get a const reference to the derived iterator.
     [[nodiscard]] Iter const &self() const { return static_cast<const Iter &>(*this); }
 
     public:
diff --git a/c++/itertools/product.hpp b/c++/itertools/product.hpp
index f764252..ef9e9c6 100644
--- a/c++/itertools/product.hpp
+++ b/c++/itertools/product.hpp
@@ -87,10 +87,7 @@ namespace itertools {
       prod_iter(std::tuple<Iters...> its_begin, EndIters its_end) : its_begin(std::move(its_begin)), its_end(std::move(its_end)) {}
 
       private:
-      /**
-       * @brief Helper function which recursively increments the current iterators.
-       * @tparam N Iterator index to increment.
-       */
+      // Helper function to recursively increment the current iterators.
       template <int N> void _increment() {
         // increment Nth iterator
         ++std::get<N>(its);
@@ -128,10 +125,7 @@ namespace itertools {
       template <typename SentinelIter> [[nodiscard]] bool operator==(sentinel_t<SentinelIter> const &s) const { return (s.it == std::get<0>(its)); }
 
       private:
-      /**
-       * @brief Helper function to dereference all original iterators.
-       * @return Tuple containing the dereferenced values of all original iterators.
-       */
+      // Helper function to dereference all original iterators.
       template <size_t... Is> [[gnu::always_inline]] [[nodiscard]] auto tuple_map_impl(std::index_sequence<Is...>) const {
         return std::tuple<decltype(*std::get<Is>(its))...>(*std::get<Is>(its)...);
       }
@@ -174,12 +168,12 @@ namespace itertools {
       [[nodiscard]] bool operator==(multiplied const &) const = default;
 
       private:
-      /// Helper function to create a detail::prod_iter representing the beginning of the product range.
+      // Helper function to create a detail::prod_iter representing the beginning of the product range.
       template <size_t... Is> [[gnu::always_inline]] auto _begin(std::index_sequence<Is...>) {
         return iterator{std::make_tuple(std::begin(std::get<Is>(tu))...), std::make_tuple(std::end(std::get<Is>(tu))...)};
       }
 
-      /// Const version of _begin(std::index_sequence<Is...>).
+      // Const version of _begin(std::index_sequence<Is...>).
       template <size_t... Is> [[gnu::always_inline]] auto _cbegin(std::index_sequence<Is...>) const {
         return const_iterator{std::make_tuple(std::cbegin(std::get<Is>(tu))...), std::make_tuple(std::cend(std::get<Is>(tu))...)};
       }
@@ -214,13 +208,7 @@ namespace itertools {
     // Class template argument deduction guide.
     template <typename... Rs> multiplied(Rs &&...) -> multiplied<std::decay_t<Rs>...>;
 
-    /**
-     * @brief Helper function to create a product range from a container of ranges.
-     *
-     * @tparam C Container type.
-     * @param cont Container of ranges.
-     * @return Product range from the ranges in the container.
-     */
+    // Helper function to create a product range from a container of ranges.
     template <typename C, size_t... Is> [[gnu::always_inline]] [[nodiscard]] auto make_product_impl(C &cont, std::index_sequence<Is...>) {
       return product(cont[Is]...);
     }
diff --git a/c++/itertools/range.hpp b/c++/itertools/range.hpp
index 6db3bb5..d3ad4f4 100644
--- a/c++/itertools/range.hpp
+++ b/c++/itertools/range.hpp
@@ -77,13 +77,13 @@ namespace itertools {
    * See also <a href="https://en.cppreference.com/w/cpp/ranges/iota_view">std::ranges::views::iota</a>.
    */
   class range {
-    /// First value of the range.
+    // First value of the range.
     long first_ = 0;
 
-    /// Last value of the range (excluded).
+    // Last value of the range (excluded).
     long last_ = -1;
 
-    /// Number of integers between two elements of the range.
+    // Number of integers between two elements of the range.
     long step_ = 1;
 
     public:
@@ -258,19 +258,19 @@ namespace itertools {
      * @brief Beginning of the integer range.
      * @return Iterator with its current value set to the first value of the range.
      */
-    [[nodiscard]] const_iterator begin() const noexcept { return {first_, last_, step_}; }
-
-    /// Const version of begin().
     [[nodiscard]] const_iterator cbegin() const noexcept { return {first_, last_, step_}; }
 
+    /// The same as cbegin().
+    [[nodiscard]] const_iterator begin() const noexcept { return {first_, last_, step_}; }
+
     /**
      * @brief End of the range.
      * @return Iterator with its current value set to the excluded last value of the range.
      */
-    [[nodiscard]] const_iterator end() const noexcept { return {last_, last_, step_}; }
-
-    /// Const version of end().
     [[nodiscard]] const_iterator cend() const noexcept { return {last_, last_, step_}; }
+
+    /// The same as cend().
+    [[nodiscard]] const_iterator end() const noexcept { return {last_, last_, step_}; }
   };
 
   /**
@@ -307,13 +307,7 @@ namespace itertools {
   /// @cond
   namespace detail {
 
-    /**
-     * @brief Helper function to create a product range of integer ranges from a tuple or an array.
-     *
-     * @tparam T Tuple or array type.
-     * @param idxs Tuple or array containing the excluded last values of the itertools::range objects.
-     * @return Product (detail::multiplied) range of integer ranges.
-     */
+    // Helper function to create a product range of integer ranges from a tuple or an array.
     template <typename T, size_t... Is> [[gnu::always_inline]] auto product_range_impl(T const &idxs, std::index_sequence<Is...>) {
       return product_range(std::get<Is>(idxs)...);
     }
diff --git a/c++/itertools/stride.hpp b/c++/itertools/stride.hpp
index fecb2cd..aacfbd4 100644
--- a/c++/itertools/stride.hpp
+++ b/c++/itertools/stride.hpp
@@ -108,10 +108,7 @@ namespace itertools {
       [[nodiscard]] bool operator==(strided const &) const = default;
 
       private:
-      /**
-       * @brief Helper function to calculate the index of the end iterator.
-       * @return Index of the end iterator.
-       */
+      // Helper function to calculate the index of the end iterator.
       [[nodiscard]] std::ptrdiff_t end_offset() const {
         auto size = distance(std::cbegin(rg), std::cend(rg));
         return (size == 0) ? 0 : ((size - 1) / stride + 1) * stride;
diff --git a/c++/itertools/zip.hpp b/c++/itertools/zip.hpp
index b288a92..45ec6ba 100644
--- a/c++/itertools/zip.hpp
+++ b/c++/itertools/zip.hpp
@@ -60,7 +60,7 @@ namespace itertools {
       zip_iter(std::tuple<Iters...> its) : its(std::move(its)) {}
 
       private:
-      /// Helper function which increments all original iterators.
+      // Helper function which increments all original iterators.
       template <size_t... Is> [[gnu::always_inline]] void increment_all(std::index_sequence<Is...>) { ((void)(++std::get<Is>(its)), ...); }
 
       public:
@@ -92,10 +92,7 @@ namespace itertools {
       }
 
       private:
-      /**
-       * @brief Helper function to dereference all original iterators.
-       * @return Tuple containing the dereferenced values of all original iterators.
-       */
+      // Helper function to dereference all original iterators.
       template <size_t... Is> [[nodiscard]] auto tuple_map_impl(std::index_sequence<Is...>) const {
         return std::tuple<decltype(*std::get<Is>(its))...>(*std::get<Is>(its)...);
       }
@@ -141,19 +138,12 @@ namespace itertools {
       [[nodiscard]] bool operator==(zipped const &) const = default;
 
       private:
-      /**
-       * @brief Helper function that applies a given callable to each range in the stored tuple and returns a
-       * new tuple with the results.
-       *
-       * @tparam F Callable type.
-       * @param f Callable object.
-       * @return Tuple containing the mapped tuple elements after applying the callable.
-       */
+      // Helper function that applies a given callable to each range in the stored tuple and returns a new tuple with the results.
       template <typename F, size_t... Is> [[gnu::always_inline]] auto tuple_map(F &&f, std::index_sequence<Is...>) {
         return std::make_tuple(std::forward<F>(f)(std::get<Is>(tu))...);
       }
 
-      /// Const overload of tuple_map(F &&, std::index_sequence<Is...>).
+      // Const overload of tuple_map(F &&, std::index_sequence<Is...>).
       template <typename F, size_t... Is> [[gnu::always_inline]] auto tuple_map(F &&f, std::index_sequence<Is...>) const {
         return std::make_tuple(std::forward<F>(f)(std::get<Is>(tu))...);
       }