There's a nice research article from 2016 by doctors in northern Norway about resuscitation of frozen patients: “Nobody is dead until warm and dead”: Prolonged

There's a nice research article from 2016 by doctors in northern Norway about resuscitation of frozen patients: “Nobody is dead until warm and dead”: Prolonged resuscitation is warranted in arrested hypothermic victims also in remote areas – A retrospective study from northern Norway J. Hilmo, T. Naesheim, M. Gilbert https://www.sciencedirect.com/science/article/pii/S0300957214005243 https://www.sciencedirect.com/science/article/pii/S030095721... (open access, CC licence) Same hospital and team that treated Anna Bågenholm (mentioned in other comments, https://en.wikipedia.org/wiki/Anna_B%C3%A5genholm https://en.wikipedia.org/wiki/Anna_B%C3%A5genholm), and I guess that case is part of the study.