Link to step-67.

diff --git a/examples/step-69/step-69.cc b/examples/step-69/step-69.cc
index d97a0307d8fa0d7e047641da39cfa3992578bae8..07f7da533773c90af09bc8d25fd79c62ca6c6e3d 100644 (file)
--- a/examples/step-69/step-69.cc
+++ b/examples/step-69/step-69.cc
@@ -421,7 +421,8 @@ namespace Step69
   // <a href="https://en.wikipedia.org/wiki/Schlieren">Schlieren</a>
   // postprocessing is a standard method for enhancing the contrast of a
   // visualization inspired by actual experimental X-ray and shadowgraphy
-  // techniques of visualization.
+  // techniques of visualization. (See step-67 for another example where we
+  // create a Schlieren plot.)
   template <int dim>
   class SchlierenPostprocessor : public ParameterAcceptor
   {