Ladewig Petersen, E. (1998). Erik Ringmar: Identity, Interest and Action: A culturel explanation of Sweden’s intervention in the Thirty Years War. (Cambridge University Press, 1996). 284 s., 40 £. Historie/Jyske Samlinger, (1), 187. Hentet fra https://tidsskrift.dk/historiejyskesamling/article/view/37813