diff --git a/deblur/deblur_2d.py b/deblur/deblur_2d.py
index fd5da19..4285c62 100644
--- a/deblur/deblur_2d.py
+++ b/deblur/deblur_2d.py
@@ -5,6 +5,11 @@ from scipy.sparse.linalg import spsolve
 import cv2
 import matplotlib.pyplot as plt
 
+"""
+https://setosa.io/ev/image-kernels/
+https://openaccess.thecvf.com/content/CVPR2021/papers/Tran_Explore_Image_Deblurring_via_Encoded_Blur_Kernel_Space_CVPR_2021_paper.pdf
+"""
+
 def show(img):
     cv2.imshow('image',img.astype(np.uint8))
     cv2.waitKey(0)