Franzén, B. 2013. Nils Hybel and Bjørn Poulsen: The Danish resources c. 1000-1550. Growth and recession. Leiden, Brill, 2007. Historisk Tidsskrift. 108, 2 (feb. 2013), 574–580. DOI:https://doi.org/10.7146/ht.v108i2.56382.