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Dijk DJ, Cajochen C, Borbély AA.Dijk DJ, et al. Among authors: borbely aa.Neurosci Lett. 1991 Jan 2;121(1-2):59-62. doi: 10.1016/0304-3940(91)90649-e.Neurosci Lett. 1991.PMID: 2020391