diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..567609b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+build/
diff --git a/.gitmodules b/.gitmodules
index a89889c..19d788d 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,3 @@
 [submodule "cmake/modules"]
 	path = cmake/modules
-	url = b3rgmann@git.bergmann89.de:cpp/CmakeModules.git
+	url = https://git.bergmann89.de/cpp/CmakeModules.git
diff --git a/CMakeLists.txt b/CMakeLists.txt
index a0512dd..6e565e2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -20,7 +20,6 @@ EndIf                             ( )
 
 # Project #########################################################################################
 
-Include                           ( CTest )
 Include                           ( GNUInstallDirs )
 Include                           ( ${CMAKE_CURRENT_SOURCE_DIR}/cmake/cppmp-options.cmake )
 Include                           ( ${CMAKE_CURRENT_SOURCE_DIR}/cmake/cppmp-const.cmake )
@@ -28,6 +27,7 @@ Include                           ( ${CMAKE_CURRENT_SOURCE_DIR}/cmake/cppmp-var.
 Project                           ( ${CPPMP_PROJECT_NAME}
                                     DESCRIPTION "${CPPMP_PROJECT_DESCRIPTION}"
                                     VERSION "${CPPMP_VERSION}" )
+Include                           ( CTest )
 
 # Subdirectories
 Add_SubDirectory                  ( ${CMAKE_CURRENT_SOURCE_DIR}/src )
diff --git a/cmake/cppmp-const.cmake b/cmake/cppmp-const.cmake
index 2951638..a848bd1 100644
--- a/cmake/cppmp-const.cmake
+++ b/cmake/cppmp-const.cmake
@@ -23,6 +23,6 @@ Set                             ( CPPMP_INSTALL_DIR_SHARE       "${CMAKE_INSTALL
 
 # C Standard
 Set                             ( CMAKE_C_STANDARD                      11 )
-Set                             ( CMAKE_CXX_STANDARD                    17 )
+Set                             ( CMAKE_CXX_STANDARD                    14 )
 Set                             ( CMAKE_C_STANDARD_REQUIRED             ON )
 Set                             ( CMAKE_CXX_STANDARD_REQUIRED           ON )
diff --git a/include/cppmp/core/constants.h b/include/cppmp/core/constants.h
index 967033f..694b792 100644
--- a/include/cppmp/core/constants.h
+++ b/include/cppmp/core/constants.h
@@ -1,4 +1,4 @@
-#pragma onec
+#pragma once
 
 #include "types.h"
 
diff --git a/include/cppmp/misc/getter.inl b/include/cppmp/misc/getter.inl
index 907322e..ce40246 100644
--- a/include/cppmp/misc/getter.inl
+++ b/include/cppmp/misc/getter.inl
@@ -84,8 +84,8 @@ namespace cppmp
             struct getter_member_func
                 : public tag_getter
             {
-                using object_type = T_object;
-                using value_type  = T_value;
+                using object_type = decay_t<T_object>;
+                using value_type  = decay_t<T_value>;
                 using member_type = T_member;
 
                 member_type member;
@@ -168,6 +168,55 @@ namespace cppmp
                 { return getter_lambda(std::forward<lambda_type>(lambda)); }
         };
 
+        /* getter_builder - chain */
+
+        template<typename T_first, typename T_second, typename... T_rest>
+        struct getter_builder<
+            list<T_first, T_second, T_rest...>,
+            enable_if_t<
+                    is_valid_v<decltype(make_getter(std::declval<T_first>()))>
+                &&  is_valid_v<decltype(make_getter(std::declval<T_second>(), std::declval<T_rest>()...))>
+            >
+        >
+        {
+            struct getter_chain
+                : public tag_getter
+            {
+                using first_getter_type  = decltype(make_getter(std::declval<T_first>()));
+                using second_getter_type = decltype(make_getter(std::declval<T_second>(), std::declval<T_rest>()...));
+                using object_type        = typename first_getter_type::object_type;
+                using value_type         = typename second_getter_type::value_type;;
+
+                first_getter_type   first;
+                second_getter_type  second;
+
+                constexpr getter_chain(
+                    first_getter_type&&     p_first,
+                    second_getter_type&&    p_second)
+                    : first (std::move(p_first))
+                    , second(std::move(p_second))
+                    { }
+
+                constexpr getter_chain(getter_chain&&) = default;
+                constexpr getter_chain(const getter_chain&) = default;
+
+                constexpr getter_chain& operator = (getter_chain&&) = default;
+                constexpr getter_chain& operator = (const getter_chain&) = default;
+
+                template<typename X_object>
+                constexpr decltype(auto) operator()(X_object&& obj) const
+                    { return second(first(std::forward<X_object>(obj))); }
+            };
+
+            template<typename X_first, typename... X_rest>
+            static constexpr decltype(auto) apply(X_first&& first, X_rest&&... rest)
+            {
+                return getter_chain(
+                    make_getter(std::forward<X_first>(first)),
+                    make_getter(std::forward<X_rest>(rest)...));
+            }
+        };
+
     }
 
     /* is_getter */
diff --git a/include/cppmp/misc/setter.inl b/include/cppmp/misc/setter.inl
index f45047b..6574aad 100644
--- a/include/cppmp/misc/setter.inl
+++ b/include/cppmp/misc/setter.inl
@@ -83,8 +83,8 @@ namespace cppmp
             struct setter_member_func
                 : public tag_setter
             {
-                using object_type = T_object;
-                using value_type  = T_value;
+                using object_type = decay_t<T_object>;
+                using value_type  = decay_t<T_value>;
                 using member_type = T_member;
 
                 member_type member;
@@ -101,7 +101,7 @@ namespace cppmp
 
                 template<typename X_object, typename X_value>
                 constexpr void operator()(X_object&& obj, X_value&& value) const
-                    { (std::forward<X_object>(obj).*member)(value); }
+                    { (std::forward<X_object>(obj).*member)(std::forward<X_value>(value)); }
             };
 
             using object_type = T_object;
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index c284fb9..868e672 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -45,7 +45,7 @@ ForEach                     ( FILE IN LISTS CPPMP_TEST_SOURCE_FILES )
 
     # test
     If                          ( HAS_CMAKE_TESTS )
-        Add_CMake_Test              ( NAME ${TEST_NAME} TARGET ${TEST_NAME} )
+        Add_CMake_Test              ( NAME ${TEST_NAME} TARGET ${TEST_NAME} GROUP cppmp )
     Else                        ( )
         Add_Test                    ( NAME ${TEST_NAME} COMMAND ${TEST_NAME} WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR} )
     EndIf                       ( )
diff --git a/test/cppmp/cppmp_traits_test.cpp b/test/cppmp/cppmp_traits_test.cpp
index ee0776c..505216b 100644
--- a/test/cppmp/cppmp_traits_test.cpp
+++ b/test/cppmp/cppmp_traits_test.cpp
@@ -12,44 +12,62 @@ struct test_obj
     static std::string sget();
 };
 
-constexpr decltype(auto) cpp_traits_lambda = [](std::string, int)->bool { return true; };
+const test_obj& static_fuu()
+{
+    static const test_obj value;
+    return value;
+}
+
+decltype(auto) cpp_traits_lambda = [](std::string, int)->bool { return true; };
 
 using type0 = ::cppmp::lambda_traits<decltype(&test_obj::test)>;
 using type1 = ::cppmp::lambda_traits<decltype(&test_obj::ctest)>;
 using type2 = ::cppmp::lambda_traits<decltype(&test_obj::sget)>;
 using type3 = ::cppmp::lambda_traits<std::string(*)(bool)>;
 using type4 = ::cppmp::lambda_traits<decltype(cpp_traits_lambda)>;
+using type5 = ::cppmp::lambda_traits<decltype(&static_fuu)>;
+
+static_assert(is_same_v<typename type0::object_type,            test_obj>,                          "");
+static_assert(is_same_v<typename type0::return_type,            int>,                               "");
+static_assert(is_same_v<typename type0::arguments_type,         std::tuple<int>>,                   "");
+static_assert(                   type0::is_mutable_v     ==     true,                               "");
+static_assert(                   type0::is_static_v      ==     false,                              "");
+static_assert(                   type0::argument_count_v ==     1,                                  "");
+
+static_assert(is_same_v<typename type1::object_type,            test_obj>,                          "");
+static_assert(is_same_v<typename type1::return_type,            double>,                            "");
+static_assert(is_same_v<typename type1::arguments_type,         std::tuple<float, std::string>>,    "");
+static_assert(                   type1::is_mutable_v     ==     false,                              "");
+static_assert(                   type1::is_static_v      ==     false,                              "");
+static_assert(                   type1::argument_count_v ==     2,                                  "");
+
+static_assert(is_same_v<typename type2::object_type,            void>,                              "");
+static_assert(is_same_v<typename type2::return_type,            std::string>,                       "");
+static_assert(is_same_v<typename type2::arguments_type,         std::tuple<>>,                      "");
+static_assert(                   type2::is_mutable_v     ==     false,                              "");
+static_assert(                   type2::is_static_v      ==     true,                               "");
+static_assert(                   type2::argument_count_v ==     0,                                  "");
 
-static_assert(is_same_v<typename type0::object_type,            test_obj>);
-static_assert(is_same_v<typename type0::return_type,            int>);
-static_assert(is_same_v<typename type0::arguments_type,         std::tuple<int>>);
-static_assert(                   type0::is_mutable_v     ==     true);
-static_assert(                   type0::is_static_v      ==     false);
-static_assert(                   type0::argument_count_v ==     1);
-
-static_assert(is_same_v<typename type1::object_type,            test_obj>);
-static_assert(is_same_v<typename type1::return_type,            double>);
-static_assert(is_same_v<typename type1::arguments_type,         std::tuple<float, std::string>>);
-static_assert(                   type1::is_mutable_v     ==     false);
-static_assert(                   type1::is_static_v      ==     false);
-static_assert(                   type1::argument_count_v ==     2);
-
-static_assert(is_same_v<typename type2::object_type,            void>);
-static_assert(is_same_v<typename type2::return_type,            std::string>);
-static_assert(is_same_v<typename type2::arguments_type,         std::tuple<>>);
-static_assert(                   type2::is_mutable_v     ==     false);
-static_assert(                   type2::is_static_v      ==     true);
-static_assert(                   type2::argument_count_v ==     0);
-
-static_assert(is_same_v<typename type3::object_type,            void>);
-static_assert(is_same_v<typename type3::return_type,            std::string>);
-static_assert(is_same_v<typename type3::arguments_type,         std::tuple<bool>>);
-static_assert(                   type3::is_mutable_v     ==     false);
-static_assert(                   type3::is_static_v      ==     true);
-static_assert(                   type3::argument_count_v ==     1);
-
-static_assert(is_same_v<typename type4::return_type,            bool>);
-static_assert(is_same_v<typename type4::arguments_type,         std::tuple<std::string, int>>);
-static_assert(                   type4::is_mutable_v     ==     false);
-static_assert(                   type4::is_static_v      ==     false);
-static_assert(                   type4::argument_count_v ==     2);
+static_assert(is_same_v<typename type3::object_type,            void>,                              "");
+static_assert(is_same_v<typename type3::return_type,            std::string>,                       "");
+static_assert(is_same_v<typename type3::arguments_type,         std::tuple<bool>>,                  "");
+static_assert(                   type3::is_mutable_v     ==     false,                              "");
+static_assert(                   type3::is_static_v      ==     true,                               "");
+static_assert(                   type3::argument_count_v ==     1,                                  "");
+
+static_assert(is_same_v<typename type4::return_type,            bool>,                              "");
+static_assert(is_same_v<typename type4::arguments_type,         std::tuple<std::string, int>>,      "");
+static_assert(                   type4::is_mutable_v     ==     false,                              "");
+static_assert(                   type4::is_static_v      ==     false,                              "");
+static_assert(                   type4::argument_count_v ==     2,                                  "");
+
+static_assert(is_same_v<typename type5::return_type,            const test_obj&>,                   "");
+static_assert(is_same_v<typename type5::arguments_type,         std::tuple<>>,                      "");
+static_assert(                   type5::is_mutable_v     ==     false,                              "");
+static_assert(                   type5::is_static_v      ==     true,                               "");
+static_assert(                   type5::argument_count_v ==     0,                                  "");
+
+TEST(cppmp_traits_test, dummy)
+{
+    (void)cpp_traits_lambda;
+}