I am afraid I have had to revert this change. The referenced cited is in violation of an Arbitration Committee ruling, specifically Wikipedia:Arbitration/Requests/Case/Antisemitism in Poland#Article sourcing expectations which states "The sourcing expectations applied to the article Collaboration in German-occupied Poland are expanded and adapted to cover all articles on the topic of Polish history during World War II (1933-45), including the Holocaust in Poland. Only high quality sources may be used, specifically peer-reviewed scholarly journals, academically focused books by reputable publishers, and/or articles published by reputable institutions. English-language sources are preferred over non-English ones when available and of equal quality and relevance. Editors repeatedly failing to meet this standard may be topic-banned as an arbitration enforcement action." That means websites such as www.holocaustresearchproject.org are unacceptable sorry, even though it was already used in the article. FDW777 (talk) 10:41, 1 December 2019 (UTC)
