Add some comments about typos in references

mbtrack2/impedance/resistive_wall.py

@@ -186,8 +186,11 @@ class CircularResistiveWall(WakeField):
         to the characteristic time t0.
         
         Eq. (11) in [1] is completely identical to Eq. (25) in [2].
-        Corrected the typos in the last two terms in exact expression
-        (Eq. (11), of [1]).
+
+        There are typos in both Eq. (11) in [1] and Eq. (25) in [2].
+        Corrected the typos in the last two terms of exact expression
+        for transverse wake function in Eq. (11), of [1].
+        It is necessary to multiply Eq. (25) in [2] by c*t0.
 
         Parameters
         ----------