Hansen, Birger. “Climatic Changes on a Yearly to Millennial Basis: Geological, Historical and Instrumental Records: Proceedings of the Second Nordic Symposium on Climatic Changes and Related Problems, Held in Stockholm, Sweden, May 16-20, 1983. Ed. By N.-A. Morner and W. Karlen. Reidel, Dordrecht 1984.”. Geografisk Tidsskrift 87 (januar 1, 1987). Set februar 25, 2021. https://tidsskrift.dk/geografisktidsskrift/article/view/44458.