diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 3a4b4294a1..f74a0211fa 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -114,8 +114,8 @@ add_subdirectory(tests/frontends/lean)
 include(StyleCheck)
 file(GLOB_RECURSE LEAN_SOURCES
          ${LEAN_SOURCE_DIR}
-         ${LEAN_SOURCE_DIR}/*.cpp
-         ${LEAN_SOURCE_DIR}/*.h)
+         ${LEAN_SOURCE_DIR}/[A-Za-z]*.cpp
+         ${LEAN_SOURCE_DIR}/[A-Za-z]*.h)
 add_style_check_target(style "${LEAN_SOURCES}")
 add_test(NAME style_check
   COMMAND ${LEAN_SOURCE_DIR}/cmake/Modules/cpplint.py ${LEAN_SOURCES})
\ No newline at end of file