diff --git a/lemon/Makefile.am b/lemon/Makefile.am
--- a/lemon/Makefile.am
+++ b/lemon/Makefile.am
@@ -69,8 +69,9 @@
 	lemon/color.h \
 	lemon/concept_check.h \
 	lemon/connectivity.h \
+	lemon/core.h \
+	lemon/cost_scaling.h \
 	lemon/counter.h \
-	lemon/core.h \
 	lemon/cplex.h \
 	lemon/dfs.h \
 	lemon/dijkstra.h \