The book telling about Birlkarl network is "Aggressive and Violent Peasant Elites in the Nordic Countries, C. 1500-1700". Actually the history starts from 1300, but we have very little documents before 1500, only king's letters and court documents. The book describes individuals and social networks, so from the 1500s.

This book investigates the forms that the aggression and violence of peasant elites could take in early modern Fennoscandia, and their role within society. The contributors highlight the social stratification, inner divisions, contradictions and conflicts of the peasant communities, but also pay attention to the elite as leaders of resistance against the authorities. With the formation of more centralised states, the elites’ status and room for agency diminished, but regional and temporal variations were great in this relatively drawn-out process, and there still remained several favourable contexts for their agency. Even though the peasant elite was not a homogenous entity, the chapters in this collection present us one uniting feature – the peasant elites’ tendency to assert themselves with an active and aggressive agency, even if this led to very different outcomes.