https://www.wilsoncenter.org/blog-post/helmut-kohl-collection-new-resource-post-cold-war-history
https://theconversation.com/tres-preguntas-sobre-la-amnistia-claves-para-el-futuro-de-espana-216937
https://www.lobbycontrol.de/parteienfinanzierung/parteispenden-deutschland-ist-das-intransparenteste-land-in-europa-115718/