diff --git a/dune/common/test/fmatrixtest.cc b/dune/common/test/fmatrixtest.cc
index 7d7b4da4fdb470d10b0d2732868df0d8fe8524f1..53a131ff64237f2567da58b66d29da97d3d3e9fa 100644
--- a/dune/common/test/fmatrixtest.cc
+++ b/dune/common/test/fmatrixtest.cc
@@ -476,6 +476,13 @@ void test_ev()
 
   // test results
   Dune::FieldVector<ft,8> ref;
+  /*
+     reference solution computed with octave 3.2
+
+     > format long e
+     > eig(rosser())
+
+   */
   ref <<=
     -1.02004901843000e+03,
   -4.14362871168386e-14,