matplotlib
diff --git a/‎tutorials/colors/colormaps.py‎
Lines changed: 1 addition & 1 deletion b/‎tutorials/colors/colormaps.py‎
Lines changed: 1 addition & 1 deletion
@@ -417,4 +417,4 @@ def plot_color_gradients(cmap_category, cmap_list):
 # .. [bw] http://www.tannerhelland.com/3643/grayscale-image-algorithm-vb6/
 # .. [colorblindness] http://www.color-blindness.com/
 # .. [vischeck] http://www.vischeck.com/vischeck/
-# .. [IBM] https://ieeexplore.ieee.org/document/480803/
+# .. [IBM] https://dx.doi.org/10.1109/VISUAL.1995.480803