Breuning Madsen, H. (1987) “Soil map of the European Communities 1:1.000.000. Commision of the European Communities, Directorate-General for Agriculture Coordination of Agricultural Research.”, Geografisk Tidsskrift, 87. Tilgængelig hos: https://tidsskrift.dk/geografisktidsskrift/article/view/44491 (Set: 1marts2021).