diff --git a/scripts/gvom.py b/scripts/gvom.py
index d085e12..2d224bc 100755
--- a/scripts/gvom.py
+++ b/scripts/gvom.py
@@ -1440,6 +1440,8 @@ def __calculate_eigenvalues(voxels_eigenvalues,metrics,cell_count):
         yy = metrics[i,6]
         yz = metrics[i,7]
         zz = metrics[i,8]
+        
+        # https://en.wikipedia.org/wiki/Eigenvalue_algorithm#3%C3%973_matrices
 
         p1 = xy*xy + xz*xz + yz*yz  
         q = (xx + yy + zz ) / 3.0