diff --git a/core-buffer/CMakeLists.txt b/core-buffer/CMakeLists.txt
index 78a8d21..123d807 100644
--- a/core-buffer/CMakeLists.txt
+++ b/core-buffer/CMakeLists.txt
@@ -3,6 +3,7 @@ file(GLOB SOURCES
 
 add_library(core-buffer STATIC ${SOURCES})
 target_include_directories(core-buffer PUBLIC include/)
+target_include_directories(core-buffer PUBLIC external/)
 target_link_libraries(core-buffer core-writer)
 
 if(CMAKE_BUILD_TYPE STREQUAL "Debug")
diff --git a/core-writer/external/date.h b/core-buffer/external/date.h
similarity index 100%
rename from core-writer/external/date.h
rename to core-buffer/external/date.h