diff --git a/eo/src/eoTruncatedSelectOne.h b/eo/src/eoTruncatedSelectOne.h
index 8cc4db1b..b65739c4 100644
--- a/eo/src/eoTruncatedSelectOne.h
+++ b/eo/src/eoTruncatedSelectOne.h
@@ -31,6 +31,7 @@
 //-----------------------------------------------------------------------------
 #include <eoSelect.h>
 #include <eoSelectOne.h>
+#include <utils/eoHowMany.h>
 #include <math.h>
 //-----------------------------------------------------------------------------