diff --git a/README.md b/README.md
index 5416cb4..c85674c 100644
--- a/README.md
+++ b/README.md
@@ -102,7 +102,7 @@ enum class Color { RED = 2, BLUE = 4, GREEN = 8 };
 * Enum value sequence
 
   ```cpp
-  constexpr auto colors = magic_enum::enum_values<Color>();
+  constexpr auto& colors = magic_enum::enum_values<Color>();
   // colors -> {Color::RED, Color::BLUE, Color::GREEN}
   // colors[0] -> Color::RED
   ```
@@ -125,7 +125,7 @@ enum class Color { RED = 2, BLUE = 4, GREEN = 8 };
 * Enum names sequence
 
   ```cpp
-  constexpr auto color_names = magic_enum::enum_names<Color>();
+  constexpr auto& color_names = magic_enum::enum_names<Color>();
   // color_names -> {"RED", "BLUE", "GREEN"}
   // color_names[0] -> "RED"
   ```
@@ -133,7 +133,7 @@ enum class Color { RED = 2, BLUE = 4, GREEN = 8 };
 * Enum entries sequence
 
   ```cpp
-  constexpr auto color_entries = magic_enum::enum_entries<Color>();
+  constexpr auto& color_entries = magic_enum::enum_entries<Color>();
   // color_entries -> {{Color::RED, "RED"}, {Color::BLUE, "BLUE"}, {Color::GREEN, "GREEN"}}
   // color_entries[0].first -> Color::RED
   // color_entries[0].second -> "RED"
diff --git a/include/magic_enum.hpp b/include/magic_enum.hpp
index a888266..79294c7 100644
--- a/include/magic_enum.hpp
+++ b/include/magic_enum.hpp
@@ -226,6 +226,7 @@ inline constexpr bool is_enum_v = std::is_enum_v<T> && std::is_same_v<T, std::de
 
 constexpr std::size_t find(std::string_view str, char c) noexcept {
 #if defined(__clang__) && __clang_major__ < 9 && defined(__GLIBCXX__)
+// https://stackoverflow.com/questions/56484834/constexpr-stdstring-viewfind-last-of-doesnt-work-on-clang-8-with-libstdc
   for (std::size_t i = 0; i < str.size(); ++i) {
     if (str[i] == c) {
       return i;
diff --git a/test/test.cpp b/test/test.cpp
index 6842cc5..0cc8aab 100644
--- a/test/test.cpp
+++ b/test/test.cpp
@@ -23,7 +23,9 @@
 #define CATCH_CONFIG_MAIN
 #include <catch.hpp>
 
+#undef  MAGIC_ENUM_RANGE_MIN
 #define MAGIC_ENUM_RANGE_MIN -120
+#undef  MAGIC_ENUM_RANGE_MAX
 #define MAGIC_ENUM_RANGE_MAX 120
 #include <magic_enum.hpp>
 
@@ -310,16 +312,16 @@ TEST_CASE("enum_value") {
 TEST_CASE("enum_values") {
   REQUIRE(std::is_same_v<decltype(magic_enum::enum_values<Color>()), const std::array<Color, 3>&>);
 
-  constexpr auto s1 = enum_values<Color&>();
+  constexpr auto& s1 = enum_values<Color&>();
   REQUIRE(s1 == std::array<Color, 3>{{Color::RED, Color::GREEN, Color::BLUE}});
 
-  auto s2 = enum_values<Numbers>();
+  constexpr auto& s2 = enum_values<Numbers>();
   REQUIRE(s2 == std::array<Numbers, 3>{{Numbers::one, Numbers::two, Numbers::three}});
 
-  constexpr auto s3 = enum_values<const Directions>();
+  constexpr auto& s3 = enum_values<const Directions>();
   REQUIRE(s3 == std::array<Directions, 4>{{Directions::Left, Directions::Down, Directions::Up, Directions::Right}});
 
-  auto s4 = enum_values<number>();
+  constexpr auto& s4 = enum_values<number>();
   REQUIRE(s4 == std::array<number, 3>{{number::one, number::two, number::three}});
 }
 
@@ -327,13 +329,13 @@ TEST_CASE("enum_count") {
   constexpr auto s1 = enum_count<Color&>();
   REQUIRE(s1 == 3);
 
-  auto s2 = enum_count<Numbers>();
+  constexpr auto s2 = enum_count<Numbers>();
   REQUIRE(s2 == 3);
 
   constexpr auto s3 = enum_count<const Directions>();
   REQUIRE(s3 == 4);
 
-  auto s4 = enum_count<number>();
+  constexpr auto s4 = enum_count<number>();
   REQUIRE(s4 == 3);
 }
 
@@ -408,32 +410,32 @@ TEST_CASE("enum_name") {
 TEST_CASE("enum_names") {
   REQUIRE(std::is_same_v<decltype(magic_enum::enum_names<Color>()), const std::array<std::string_view, 3>&>);
 
-  constexpr auto s1 = enum_names<Color&>();
+  constexpr auto& s1 = enum_names<Color&>();
   REQUIRE(s1 == std::array<std::string_view, 3>{{"RED", "GREEN", "BLUE"}});
 
-  auto s2 = enum_names<Numbers>();
+  constexpr auto& s2 = enum_names<Numbers>();
   REQUIRE(s2 == std::array<std::string_view, 3>{{"one", "two", "three"}});
 
-  constexpr auto s3 = enum_names<const Directions>();
+  constexpr auto& s3 = enum_names<const Directions>();
   REQUIRE(s3 == std::array<std::string_view, 4>{{"Left", "Down", "Up", "Right"}});
 
-  auto s4 = enum_names<number>();
+  constexpr auto& s4 = enum_names<number>();
   REQUIRE(s4 == std::array<std::string_view, 3>{{"one", "two", "three"}});
 }
 
 TEST_CASE("enum_entries") {
   REQUIRE(std::is_same_v<decltype(magic_enum::enum_entries<Color>()), const std::array<std::pair<Color, std::string_view>, 3>&>);
 
-  constexpr auto s1 = enum_entries<Color&>();
+  constexpr auto& s1 = enum_entries<Color&>();
   REQUIRE(s1 == std::array<std::pair<Color, std::string_view>, 3>{{{Color::RED, "RED"}, {Color::GREEN, "GREEN"}, {Color::BLUE, "BLUE"}}});
 
-  auto s2 = enum_entries<Numbers>();
+  constexpr auto& s2 = enum_entries<Numbers>();
   REQUIRE(s2 == std::array<std::pair<Numbers, std::string_view>, 3>{{{Numbers::one, "one"}, {Numbers::two, "two"}, {Numbers::three, "three"}}});
 
-  constexpr auto s3 = enum_entries<Directions&>();
+  constexpr auto& s3 = enum_entries<Directions&>();
   REQUIRE(s3 == std::array<std::pair<Directions, std::string_view>, 4>{{{Directions::Left, "Left"}, {Directions::Down, "Down"}, {Directions::Up, "Up"}, {Directions::Right, "Right"}}});
 
-  auto s4 = enum_entries<number>();
+  constexpr auto& s4 = enum_entries<number>();
   REQUIRE(s4 == std::array<std::pair<number, std::string_view>, 3>{{{number::one, "one"}, {number::two, "two"}, {number::three, "three"}}});
 }
 
diff --git a/test/test_flags.cpp b/test/test_flags.cpp
index 3c64000..57375b9 100644
--- a/test/test_flags.cpp
+++ b/test/test_flags.cpp
@@ -23,8 +23,6 @@
 #define CATCH_CONFIG_MAIN
 #include <catch.hpp>
 
-#define MAGIC_ENUM_RANGE_MIN -120
-#define MAGIC_ENUM_RANGE_MAX 120
 #include <magic_enum.hpp>
 
 #include <array>
@@ -487,16 +485,16 @@ TEST_CASE("enum_value") {
 TEST_CASE("enum_values") {
   REQUIRE(std::is_same_v<decltype(magic_enum::enum_values<Color>()), const std::array<Color, 3>&>);
 
-  constexpr auto s1 = enum_values<Color&>();
+  constexpr auto& s1 = enum_values<Color&>();
   REQUIRE(s1 == std::array<Color, 3>{{Color::RED, Color::GREEN, Color::BLUE}});
 
-  auto s2 = enum_values<Numbers>();
+  constexpr auto& s2 = enum_values<Numbers>();
   REQUIRE(s2 == std::array<Numbers, 4>{{Numbers::one, Numbers::two, Numbers::three, Numbers::many}});
 
-  constexpr auto s3 = enum_values<const Directions>();
+  constexpr auto& s3 = enum_values<const Directions>();
   REQUIRE(s3 == std::array<Directions, 4>{{Directions::Left, Directions::Down, Directions::Up, Directions::Right}});
 
-  auto s4 = enum_values<number>();
+  constexpr auto& s4 = enum_values<number>();
   REQUIRE(s4 == std::array<number, 4>{{number::one, number::two, number::three, number::four}});
 }
 
@@ -504,13 +502,13 @@ TEST_CASE("enum_count") {
   constexpr auto s1 = enum_count<Color&>();
   REQUIRE(s1 == 3);
 
-  auto s2 = enum_count<Numbers>();
+  constexpr auto s2 = enum_count<Numbers>();
   REQUIRE(s2 == 4);
 
   constexpr auto s3 = enum_count<const Directions>();
   REQUIRE(s3 == 4);
 
-  auto s4 = enum_count<number>();
+  constexpr auto s4 = enum_count<number>();
   REQUIRE(s4 == 4);
 }
 
@@ -561,32 +559,32 @@ TEST_CASE("enum_name") {
 TEST_CASE("enum_names") {
   REQUIRE(std::is_same_v<decltype(magic_enum::enum_names<Color>()), const std::array<std::string_view, 3>&>);
 
-  constexpr auto s1 = enum_names<Color&>();
+  constexpr auto& s1 = enum_names<Color&>();
   REQUIRE(s1 == std::array<std::string_view, 3>{{"RED", "GREEN", "BLUE"}});
 
-  auto s2 = enum_names<Numbers>();
+  constexpr auto& s2 = enum_names<Numbers>();
   REQUIRE(s2 == std::array<std::string_view, 4>{{"one", "two", "three", "many"}});
 
-  constexpr auto s3 = enum_names<const Directions>();
+  constexpr auto& s3 = enum_names<const Directions>();
   REQUIRE(s3 == std::array<std::string_view, 4>{{"Left", "Down", "Up", "Right"}});
 
-  auto s4 = enum_names<number>();
+  constexpr auto& s4 = enum_names<number>();
   REQUIRE(s4 == std::array<std::string_view, 4>{{"one", "two", "three", "four"}});
 }
 
 TEST_CASE("enum_entries") {
   REQUIRE(std::is_same_v<decltype(magic_enum::enum_entries<Color>()), const std::array<std::pair<Color, std::string_view>, 3>&>);
 
-  constexpr auto s1 = enum_entries<Color&>();
+  constexpr auto& s1 = enum_entries<Color&>();
   REQUIRE(s1 == std::array<std::pair<Color, std::string_view>, 3>{{{Color::RED, "RED"}, {Color::GREEN, "GREEN"}, {Color::BLUE, "BLUE"}}});
 
-  auto s2 = enum_entries<Numbers>();
+  constexpr auto& s2 = enum_entries<Numbers>();
   REQUIRE(s2 == std::array<std::pair<Numbers, std::string_view>, 4>{{{Numbers::one, "one"}, {Numbers::two, "two"}, {Numbers::three, "three"}, {Numbers::many, "many"}}});
 
-  constexpr auto s3 = enum_entries<Directions&>();
+  constexpr auto& s3 = enum_entries<Directions&>();
   REQUIRE(s3 == std::array<std::pair<Directions, std::string_view>, 4>{{{Directions::Left, "Left"}, {Directions::Down, "Down"}, {Directions::Up, "Up"}, {Directions::Right, "Right"}}});
 
-  auto s4 = enum_entries<number>();
+  constexpr auto& s4 = enum_entries<number>();
   REQUIRE(s4 == std::array<std::pair<number, std::string_view>, 4>{{{number::one, "one"}, {number::two, "two"}, {number::three, "three"}, {number::four, "four"}}});
 }