diff --git a/CMakeLists.txt b/CMakeLists.txt
index e34b67a..724667f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,12 +13,12 @@ if(${srcdir} STREQUAL ${bindir})
  " Please remove them.")
 endif()
 
-project(odm CXX)
+project(odm C CXX)
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_INTERPROCEDURAL_OPTIMIZATION ON)
 
-include_directories(include)
+include_directories(include GSW-C)
 add_compile_options(-Wall)
 
 # Dwarf-4 support check
@@ -28,4 +28,7 @@ if(COMPILER_SUPPORTS_DWARF4 AND (CMAKE_BUILD_TYPE STREQUAL "Debug" OR CMAKE_BUIL
  add_compile_options(-gdwarf-4)
 endif()
 
+add_library(teos STATIC GSW-C/gsw_oceanographic_toolbox.c GSW-C/gsw_saar.c)
+set_target_properties(teos PROPERTIES LINKER_LANGUAGE C)
+
 add_subdirectory(src)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index aa6a96d..644922c 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -8,6 +8,6 @@ include_directories(../michlib/michlib)
 
 file(GLOB srcs *.cpp)
 add_executable(${EXENAME} ${srcs})
-target_link_libraries(${EXENAME} ${linker_options} ${netcdf} OpenMP::OpenMP_CXX)
+target_link_libraries(${EXENAME} ${linker_options} ${netcdf} OpenMP::OpenMP_CXX teos)
 set_target_properties(${EXENAME} PROPERTIES POSITION_INDEPENDENT_CODE ON)
 install(TARGETS ${EXENAME})