Outcomes and long‐term mortality after basilar artery occlusion—A cohort with up to 20 years' follow‐up. - Ritvonen, Juhani; Sairanen, Tiina; Silvennoinen, Heli; Virtanen, Pekka; Salonen, Oili; Lindsberg, Perttu J.; Strbian, Daniel (European Journal of Neurology, 2021)