diff --git a/TMA_PY3.py b/TMA_PY3.py
index c298a17..511c69c 100644
--- a/TMA_PY3.py
+++ b/TMA_PY3.py
@@ -141,6 +141,8 @@ def MergeGROMACSTrajectories(self):
         print("Merging both trajectories into one and generating .xtc...")
         print("---------------------------------------------------------")
 
+	# For GROMACS 2019.1 http://manual.gromacs.org/current/onlinehelp/gmx-trjcat.html
+	
         os.system("gmx trjcat -f %s %s -o NewMergedTrajectory.xtc" % (
             xtc1, xtc2))