Issues of sub-national referendums regulated at the national level

Denmark
Denmark, Constitution 1953, accessed 24 September 2019
Denmark, Lov om etablering af en ordning for borgerforslag med henblik på behandling i Folketinget, 17 January 2018 [in Danish], accessed 24 September 2019
Denmark Folketing (Parliamentary) Elections Act (Consolidated Act No. 369 of 10 April 2014), [in English], accessed 27 June 2019
Denmark, Bekendtgørelse om en ordning for borgerforslag med henblik på behandling i Folketinget, 17 January 2018 [in Danish], accessed 24 September 2019