diff --git a/lemon/Makefile.am b/lemon/Makefile.am
--- a/lemon/Makefile.am
+++ b/lemon/Makefile.am
@@ -13,6 +13,7 @@
 lemon_libemon_la_LDFLAGS = $(GLPK_LIBS) $(CPLEX_LIBS) $(SOPLEX_LIBS)
 
 lemon_HEADERS += \
+        lemon/dim2.h \
 	lemon/list_graph.h \
         lemon/tolerance.h