diff --git a/doc/conf.py b/doc/conf.py
index 9fb5f530f85e1..b4c944a928c3c 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -604,6 +604,8 @@ def setup(app):
     "https://doi.org/10.13140/RG.2.2.35280.02565",
     "https://www.microsoft.com/en-us/research/uploads/prod/2006/01/"
     "Bishop-Pattern-Recognition-and-Machine-Learning-2006.pdf",
+    "https://www.researchgate.net/publication/4974606_"
+    "Hedonic_housing_prices_and_the_demand_for_clean_air",
     "https://www.jstor.org/stable/2984099",
     # Broken links from testimonials
     "http://www.bestofmedia.com",