KOCH, Erich. The German Social Security System for Farmers. Ubezpieczenia w Rolnictwie – Materiały i Studia, [S. l.], n. 2/74, p. 359–386, 2020. Disponível em: https://ojs.academicon.pl/ur/article/view/10125. Acesso em: 2 lis. 2025.