Engstad, Torgeir, Tora Torgersen Engstad, Matti Viitanen, and Hanne Ellekjær. 2012. “Epidemiology of Stroke in the Elderly in the Nordic Countries. Incidence, Survival, Prevalence and Risk Factors”. Norsk Epidemiologi 22 (2). https://doi.org/10.5324/nje.v22i2.1557.