diff --git a/galleries/users_explain/colors/colormaps.py b/galleries/users_explain/colors/colormaps.py
index 263c3c72e8ea..8c97a6acb810 100644
--- a/galleries/users_explain/colors/colormaps.py
+++ b/galleries/users_explain/colors/colormaps.py
@@ -451,7 +451,7 @@ def plot_color_gradients(cmap_category, cmap_list):
 # ==========
 #
 # .. _Third-party colormaps: https://matplotlib.org/mpl-third-party/#colormaps-and-styles
-# .. [Ware] http://ccom.unh.edu/sites/default/files/publications/Ware_1988_CGA_Color_sequences_univariate_maps.pdf
+# .. [Ware] https://dl.acm.org/doi/10.1109/38.7760
 # .. [Moreland] http://www.kennethmoreland.com/color-maps/ColorMapsExpanded.pdf
 # .. [list-colormaps] https://gist.github.com/endolith/2719900#id7
 # .. [mycarta-banding] https://mycarta.wordpress.com/2012/10/14/the-rainbow-is-deadlong-live-the-rainbow-part-4-cie-lab-heated-body/