[gegl] noise-cell: add reference op meta-data

[Øyvind Kolås <ok src gnome org>]

commit 1f95e135e1a3fcd31752b26b623ed1cb2ad8c564
Author: Øyvind Kolås <pippin gimp org>
Date:   Sun Apr 3 18:22:43 2016 +0200

    noise-cell: add reference op meta-data

 operations/common/noise-cell.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)
---
diff --git a/operations/common/noise-cell.c b/operations/common/noise-cell.c
index 76a89b1..cb4217f 100644
--- a/operations/common/noise-cell.c
+++ b/operations/common/noise-cell.c
@@ -431,7 +431,13 @@ gegl_op_class_init (GeglOpClass *klass)
     "title",              _("Cell Noise"),
     "categories",         "render",
     "position-dependent", "true",
-    "description", _("Generates a cellular texture."),
+
+    "description",        _("Generates a cellular texture.  "),
+
+    "reference",  "Steven Worley. 1996. A cellular texture basis function. In
+    Proceedings of the 23rd annual conference on Computer graphics and
+    interactive techniques (SIGGRAPH '96)."
+
     NULL);
 }