Interview during 2020, published in June 2020. Here is the link.
Interview during 2020, published in September 2020. Here is the link to the article on the website of the Dutch Ministry of Business Affairs.
Article on the website of the governmental support of circular practices on 4/5/2020. Here is the link.
Article on the UIAA website about the Clean Climber event on 9/3/2019. Here is the link.
Article by Katharina Spitzley in the Rheinzeitung after the Clean Climber event on 9/3/2019.
Article in the magazine of the Dutch climbing federation NKBV in 2018.
