diff --git a/pickleball/wall-ball-app/README.md b/pickleball/wall-ball-app/README.md
index 2e534f21..f4164fe3 100644
--- a/pickleball/wall-ball-app/README.md
+++ b/pickleball/wall-ball-app/README.md
@@ -12,4 +12,10 @@ if you want to execute the script using your webcam rather than the supplied vid
 switch:
 ```
 python ball_tracking.py
-```
\ No newline at end of file
+```
+
+
+# RGB Ball color range detector
+
+https://github.com/PyImageSearch/imutils/blob/master/bin/range-detector
+
diff --git a/pickleball/wall-ball-app/ball_tracking.py b/pickleball/wall-ball-app/ball_tracking.py
index 302b2e81..b8502da1 100644
--- a/pickleball/wall-ball-app/ball_tracking.py
+++ b/pickleball/wall-ball-app/ball_tracking.py
@@ -46,6 +46,7 @@
 # define the lower and upper boundaries of the "green"
 # ball in the HSV color space, then initialize the
 # list of tracked points
+# https://github.com/PyImageSearch/imutils/blob/master/bin/range-detector
 greenLower = (29, 86, 6)
 greenUpper = (64, 255, 255)
 pts = deque(maxlen=args["buffer"])