diff --git a/README.md b/README.md
index 68ac60dcfc72c2ed8e5b41ff19fceaa861e5cca4..c2abf387118e5650a3ee2653f5f0c5aeef201458 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,8 @@ Quick Reference: http://www.musashinodenpa.com/p5/
 
 Libraries: https://processing.org/reference/libraries/
 
+Reference manual for gab.opencv: http://atduskgreg.github.io/opencv-processing/reference/
+
 Install
 
 ```
@@ -81,6 +83,8 @@ Reconstructed "ARDroneForP5.jar" is not the same as the original.
 
 Operation verification -> Maybe no problems
 
+What about the "Magic must be correct"-Exception: https://vsis-www.informatik.uni-hamburg.de/oldServer/teaching/projects/yadrone/faq/faq.html#
+
 ### Reference
 
 Related to Ant, javac, ...
@@ -96,8 +100,11 @@ Related to Drone, ...
 
 * https://github.com/kotarot/Proken-Drone2017
 
-Related to OpenCV, ...
+Related to OpenCV for Processing, ...
 
 * http://r-dimension.xsrv.jp/classes_j/opencv-for-processing/
 * https://qiita.com/TaitoOtani/items/d71aa838fcbb0a4fcd1f
+* https://yoppa.org/sfc_design17/8674.html
+* https://yoppa.org/sfc_design16/7958.html
+* http://www.d-improvement.jp/learning/processing/2011-b/06.html