diff --git a/library/cadbiom/models/clause_constraints/mcl/CLUnfolder.py b/library/cadbiom/models/clause_constraints/mcl/CLUnfolder.py
index 59d3d106ebb2c0e2437f75f99ec9b2e628f3e704..bc98ddd2535c851f7aa1959ebbf10e469dea2835 100644
--- a/library/cadbiom/models/clause_constraints/mcl/CLUnfolder.py
+++ b/library/cadbiom/models/clause_constraints/mcl/CLUnfolder.py
@@ -217,10 +217,11 @@ class CLUnfolder(object):
         """
         self.dynamic_system = dynamic_system # symbolic clause dynamic system
 
-        # shift_step equals to the total number of coded variables
+        # shift_step equals to the total number of coded variables of the system
         # (including inputs, entities, clocks/events, auxiliary variables)
+
         # shift_step_init: the shift step ss (if n is X_0 code, n+ss is X_1 code)
-        self.shift_step_init = dynamic_system.get_var_number() # shift step of system (number of variables of the system)
+        self.shift_step_init = dynamic_system.get_var_number()
         self.__shift_step = self.shift_step_init  # current shift/step
 
         # About unfolder lock and shift_step:
@@ -1225,7 +1226,7 @@ class CLUnfolder(object):
         code them into DIMACS clauses constraints (__code_clause()).
 
         __code_clause() is susceptible to add new auxiliary numeric variables
-        during this process if a variable is not found in __var_code_table or
+        during this process if a variable is not found in __var_code_table and in
         __aux_code_table.
 
         - __init_initial_constraint_0, __init_final_constraint_0, __init_invariant_constraint_0