9-Literature.md

@@ -767,6 +767,10 @@ Free-range husbandry of laying hens. Methodology for calculating the nitrogen ex
 
   http://www.ceip.at/fileadmin/inhalte/emep/Adjustments/Decision_2014_1.pdf \[20.12.2017\]
 
+##### IPSOS (2019)
+
+* Pferdesport in Deutschland. https://www.pferd-aktuell.de/relaunch/assets/filePush.php?mimeType=application/pdf&fullPath=https://www.pferd-aktuell.de/relaunch/files/2/45/Ergebnisbericht_Ipsos-Studie_2019.pdf \[07.06.2024\]
+
 ##### IUPAC – International Union of Pure and Applied Chemistry (1993)
 
 * Quantities, Units and Symbols in Physical Chemistry. 2nd ed., Blackwell, London, 160 p