Where do we find this stuff? Here are our sources:
Viking Answer Lady – Hólmgang and Einvigi: Scandinavian Forms of the Duel
New York Time Magazine – Viking Age Smallpox Complicates Story of Viral Evolution
Listverse – 10 Interesting Viking Rituals
History Extra – The Truth About Viking Berserkers
Medievalists – The Vikings, Their Worms, And The Diseases They Got
History Channel – What We Know About Vikings and Slaves
“Magical Medicine in Viking Scandinavia”, D. Robertson, Journal of Medical History (1976)
“The Vikings and Homosexuality”, Gunnora Hallakarva, Fordham University
“Hólmganga and Einvigi: Scandinavian Forms of the Duel”, Olav Bo, Medical Scandinavia (1969)
“The Old Icelandic Duel”, Marlene Ciklamini, Scandinavian Studies (1963)
“Tooth filing was a worldwide craze among Viking men”, Maev Kennedy, The Guardian (July 11, 2011)
“The Historical Encylopedia of World Slavery: Volume 1, A-K”, Junius Rodriguez, ABC-CLIO (1997)
“How the Barbarian Invasions Shaped the Modern World”, Thomas Craughwell, Fair Winds Press.
“The Sagas of the Icelanders”, Jane Smiley, Penguin Classics (2001)
“Northern Antiquities: or An Historical Account of the Manners, Customs, and Laws, Maritime Expeditions and Discoveries, Languages and Literature, of the Ancient Scandinavians”, Percy Thomas, George Woodfall & Son (1847)
“Icelandic Sagas, Vol III: The Orkneyingers’ Saga”, George Dasent (1894)
“On Going Berserk: A Neurochemical Inquiry”, Howard Fabing, Scientific Monthly (1956)
“Sports and Games in Icelandic Saga Literature”, John Martin, Scandinavian Studies (2003)
“Icelanders in the Viking Age: The People of the Sagas”, William Short, McFarland and Company (2010)
“The Vengeance of Ivarr the Boneless”, Mike Dash, Smithsonian Magazine (March 13, 2013)