Tolong jelaskan mengenai Lihat pula dari Thrall

Ben Raffield (2019) "The slave markets of the Viking world: comparative perspectives on an ‘invisible archaeology’." Slavery & Abolition, 40:4, 682-705

Thomas K. Heebøll-Holm (2020) "Piratical slave-raiding – the demise of a Viking practice in high medieval Denmark" Scandinavian Journal of History