update references

docs/references.bib

@@ -1922,3 +1922,28 @@ @article {frei_snowfall_2018
     url = {https://tc.copernicus.org/articles/12/1/2018/},
     doi = {10.5194/tc-12-1-2018}
 }
+
+@article{dawson_plant_1991,
+	title = {Plant {Hardiness} {Zones} for {Australia}},
+	volume = {89},
+	url = {https://www.cpbr.gov.au/gardens/research/hort.research/zones.html},
+	language = {en},
+	number = {8},
+	urldate = {2023-06-16},
+	journal = {Australian Horticulture},
+	author = {Dawson, Iain A.},
+	year = {1991},
+	pages = {37 -- 39},
+}
+
+
+@misc{usda_2012,
+	title = {{USDA} {Plant} {Hardiness} {Zone} {Map}},
+	url = {https://planthardiness.ars.usda.gov/},
+	abstract = {The 2012 USDA Plant Hardiness Zone Map allows gardeners and growers to determine which plants are most likely to thrive at a location. The map is based on the average annual minimum winter temperature, divided into 10-degree F zones.},
+	language = {en-ca},
+	urldate = {2023-06-16},
+	author = {{USDA Agricultural Research Service}},
+	year = {2012},
+	file = {Snapshot:/home/tjs/snap/zotero-snap/common/Zotero/storage/XT7HZ9YG/planthardiness.ars.usda.gov.html:text/html},
+}

xclim/indices/_agro.py

@@ -1451,8 +1451,8 @@ def hardiness_zones(
 
     References
     ----------
-    .. [usda] : USDA Plant Hardiness Zone Map, 2012. Agricultural Research Service, U.S. Department of Agriculture. Accessed from https://planthardiness.ars.usda.gov/
-    .. [anbg] : Dawson, I. A. (1991). Plant hardiness zones for Australia. https://www.anbg.gov.au/gardens/research/hort.research/zones.html
+    :cite:cts:`usda_2012`
+    :cite:cts:`dawson_plant_1991`
     """
     tnmin = tasmin.resample(time="YS").min().rolling(time=window).mean()