diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2d61aff..80ac50a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -237,10 +237,10 @@ list(REMOVE_ITEM  APP_SOURCES "${CMAKE_CURRENT_SOURCE_DIR}/src/Tests/CoolProp-Te
 list(REMOVE_ITEM  APP_SOURCES "${CMAKE_CURRENT_SOURCE_DIR}/src/CoolPropLib.cpp")
 
 set (APP_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}")
-list (APPEND APP_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/externals/Eigen")
-list (APPEND APP_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/externals/msgpack-c/include")
-list (APPEND APP_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/externals/fmtlib/include")
-list (APPEND APP_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/externals/fmtlib") # should be deprecated
+find_package(Eigen3 CONFIG REQUIRED)
+find_package(msgpack CONFIG REQUIRED)
+find_package(fmt CONFIG REQUIRED)
+link_libraries(Eigen3::Eigen msgpackc msgpackc-cxx fmt::fmt)
 list (APPEND APP_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/include")
 list (APPEND APP_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/src")