diff --git a/GPy/likelihoods/multioutput_likelihood.py b/GPy/likelihoods/multioutput_likelihood.py
index 7b201d60..2b407571 100644
--- a/GPy/likelihoods/multioutput_likelihood.py
+++ b/GPy/likelihoods/multioutput_likelihood.py
@@ -1,5 +1,9 @@
 # Copyright (c) 2012-2014 The GPy authors (see AUTHORS.txt)
 # Licensed under the BSD 3-clause license (see LICENSE.txt)
+# Multioutput likelihood structure is similar to the 
+# corresponding structure in GPstuff. If building complex
+# multioutput models on top of this class and need a reference,
+# check GPstuff project.
 
 import numpy as np
 from scipy import stats, special