L. Symon, Observations on the leptomeningeal collateral circulation in dogs, J Physiol, vol.154, issue.2, pp.1-14, 1960.

L. Symon, Studies of leptomeningeal collateral circulation in Macacus rhesus, J Physiol, vol.159, pp.68-86, 1961.

L. Symon, S. Ishikawa, and J. S. Meyer, Cerebral arterial pressure changes and development of leptomeningeal collateral circulation, Neurology, vol.13, pp.237-250, 1963.

L. Symon and R. W. Russell, The development of cerebral collateral circulation following occlusion of vessels in the neck. An experimental study in baboons, J Neurol Sci, vol.13, pp.197-208, 1971.

L. Symon, A comparative study of middle cerebral pressure in dogs and macaques, J Physiol, vol.191, pp.449-465, 1967.

L. Symon, P. E. Branston, and N. M. , The distribution and density of reduced cerebral blood flow following acute middle cerebral artery occlusion: an experimental study by the technique of hydrogen clearance in baboons, Stroke, vol.5, pp.355-364, 1974.

N. M. Branston, L. Symon, C. Ha, and E. Pasztor, Relationship between the cortical evoked potential and local cortical blood flow following acute middle cerebral artery occlusion in the baboon, Exp Neurol, vol.45, pp.195-208, 1974.

N. M. Branston, L. Symon, and H. A. Crockard, Recovery of the cortical evoked response following temporary middle cerebral artery occlusion in baboons: relation to local blood flow and PO2, Stroke, vol.7, pp.151-157, 1976.

D. T. Hope, N. M. Branston, and L. Symon, Restoration of neurological function with induced hypertension in acute experimental cerebral ischaemia, Acta Neurol Scand Suppl, vol.64, pp.506-507, 1977.

L. Symon, N. M. Branston, and A. J. Strong, Autoregulation in acute focal ischemia. An experimental study, Stroke, vol.7, pp.547-554, 1976.

J. Astrup, L. Symon, N. M. Branston, and N. A. Lassen, Cortical evoked potential and extracellular Kþ and Hþ at critical levels of brain ischemia, Stroke, vol.8, pp.51-57, 1977.

R. J. Harris, L. Symon, N. M. Branston, and M. Bayhan, Changes in extracellular calcium activity in cerebral ischaemia, J Cereb Blood Flow Metab, vol.1, pp.203-209, 1981.

L. Symon and J. B. Brierley, Morphological changes in cerebral blood vessels in chronic ischemic infarction: flow correlation obtained by the hydrogen clearance method, The cerebral vessel wall, pp.165-174, 1976.

J. B. Brierley and L. Symon, Extent of infarcts in baboon's brain 3 years after occlusion of the middle cerebral artery, Neuropath Exp Neurol, vol.3, pp.217-218, 1977.

L. Symon, Disordered cerebro-vascular physiology in aneurysmal subarachnoid haemorrhage, Acta Neurochir (Wien), vol.41, pp.7-22, 1978.

F. Momma, A. D. Wang, and L. Symon, Effects of temporary arterial occlusion on somatosensory evoked responses in aneurysm surgery, Surg Neurol, vol.27, pp.343-352, 1987.

J. Astrup, B. K. Siesjo, and L. Symon, Thresholds in cerebral ischemia -the ischemic penumbra, Stroke, vol.12, pp.723-725, 1981.

T. H. Jones, R. B. Morawetz, and R. M. Crowell, Thresholds of focal cerebral ischemia in awake monkeys, J Neurosurg, vol.54, pp.773-782, 1981.

R. B. Morawetz, U. Degirolami, R. G. Ojemann, F. W. Marcoux, and R. M. Crowell, Cerebral blood flow determined by hydrogen clearance during middle cerebral artery occlusion in unanesthetized monkeys, Stroke, vol.9, pp.143-149, 1978.

W. D. Heiss, Ischemic penumbra: evidence from functional imaging in man, J Cereb Blood Flow Metab, vol.20, pp.1276-1293, 2000.

J. C. Baron, Mapping the ischaemic penumbra with PET: implications for acute stroke treatment, Cerebrovasc Dis, vol.9, pp.193-201, 1999.

G. Marchal, C. Serrati, and P. Rioux, PET imaging of cerebral perfusion and oxygen consumption in acute ischaemic stroke: relation to outcome, Lancet, vol.341, pp.925-927, 1993.

B. C. Campbell and M. W. Parsons, Imaging selection for acute stroke intervention, Int J Stroke, vol.13, pp.554-567, 2018.

J. C. Baron, V. Kummer, R. Del-zoppo, and G. J. , Challenging the concept of a rigid and universal time window, Stroke, vol.26, pp.2219-2221, 1995.

G. A. Donnan, J. C. Baron, M. H. Davis, and S. M. , Penumbral selection of patients for trials of acute stroke therapy, Lancet Neurol, vol.8, pp.261-269, 2009.

F. B. Meyer, D. G. Piepgras, T. M. Sundt, and T. Yanagihara, Emergency embolectomy for acute occlusion of the middle cerebral artery, J Neurosurg, vol.62, pp.639-647, 1985.

J. A. Zivin, M. Fisher, U. Degirolami, C. C. Hemenway, and J. A. Stashak, Tissue plasminogen activator reduces neurological damage after cerebral embolism, Science, vol.230, pp.1289-1292, 1985.

L. Symon, G. A. Donnan, J. C. Baron, and S. M. Davis, The ischemic penumbra -the beginning, The ischemic penumbra. New York: Informa, pp.1-6, 2007.

J. Astrup, L. Symon, N. M. Branston, and N. A. Lassen, Thresholds of cerebral ischemia, 1977.