Bacigaluppi S, Zona G, Secci F, Spena G, Mavilio N, Brusa G, Agid R, Krings T, Ottonello G, Fontanella M. Diagnosis of cerebral vasospasm and risk of delayed cerebral ischemia related to aneurysmal subarachnoid haemorrhage: an overview of available tools. Neurosurg Rev. 2015 Oct; 38(4):603-18.