diff --git a/alib2elgo/src/automaton/properties/efficient/AllEpsilonClosure.cpp b/alib2elgo/src/automaton/properties/efficient/AllEpsilonClosure.cxx
similarity index 100%
rename from alib2elgo/src/automaton/properties/efficient/AllEpsilonClosure.cpp
rename to alib2elgo/src/automaton/properties/efficient/AllEpsilonClosure.cxx
diff --git a/alib2elgo/src/automaton/properties/efficient/Properties.cpp b/alib2elgo/src/automaton/properties/efficient/Properties.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..e741447c37d55895d5005a417bbc0048ec847ff6
--- /dev/null
+++ b/alib2elgo/src/automaton/properties/efficient/Properties.cpp
@@ -0,0 +1,3 @@
+#include "AllEpsilonClosure.cxx"
+#include "ReachableStates.cxx"
+#include "UsefulStates.cxx"
diff --git a/alib2elgo/src/automaton/properties/efficient/ReachableStates.cpp b/alib2elgo/src/automaton/properties/efficient/ReachableStates.cxx
similarity index 100%
rename from alib2elgo/src/automaton/properties/efficient/ReachableStates.cpp
rename to alib2elgo/src/automaton/properties/efficient/ReachableStates.cxx
diff --git a/alib2elgo/src/automaton/properties/efficient/UsefulStates.cpp b/alib2elgo/src/automaton/properties/efficient/UsefulStates.cxx
similarity index 100%
rename from alib2elgo/src/automaton/properties/efficient/UsefulStates.cpp
rename to alib2elgo/src/automaton/properties/efficient/UsefulStates.cxx