diff --git a/TODO b/TODO
index 2593dc07b20b55bc028888ec6f58c7eeb1c99057..89cb3ea67ea0f651882a8d5ed5dfb6541d3eda08 100644
--- a/TODO
+++ b/TODO
@@ -3,6 +3,7 @@
 expr.cpp: get_k, get_j should allow i dependence
   <= needs major modif in node.cpp
 
+history: RETURN not stored
 
 == CLEANUP ==
 
diff --git a/pub/src/mem.cpp b/pub/src/mem.cpp
index e2caeac93c701c774030d1b41b389ac10c32be67..a6281794900f505828519a2ae8f6fd937bc9ff21 100644
--- a/pub/src/mem.cpp
+++ b/pub/src/mem.cpp
@@ -261,10 +261,7 @@ namespace NOlm {
 
 namespace NOlm {
 
-    //! Store file f in online memory.
-    //!   Argument k is used only when NOlm::overwrite is on;
-    //!   it is either the file number of the file to be overwritten,
-    //!   or -1 to forbid overwriting.
+    //! Store file f in online memory. If overwrite and k!=-1, overwrite file k.
     void mem_store( POlo f, int k )
     {
         if( overwrite && k!=-1 ){
diff --git a/test/mfj.inp b/test/mfj.inp
new file mode 100644
index 0000000000000000000000000000000000000000..8107d603dddec6bce2ae1b1c860196490747e864
--- /dev/null
+++ b/test/mfj.inp
@@ -0,0 +1,13 @@
+# test mfj
+fm
+20
+5
+
+fm
+20
+4
+
+0,1 mfj
+0,1 mfj=
+df
+