Patricia R. Casey, Brendan Kelly (2007), Fish's Clinical Psychopathology: Signs and Symptoms in PsychiatryRCPsych Publications, Retrieved 20 January 2012; ISBN1-904671-32-2
Karl Leonhard, Professor of Psychiatry and Neurology - Cycloid Psychoses—Endogenous Psychoses which are neither Schizophrenic nor Manic-Depressive The British Journal of Psychiatry (1961) 107: 633-648 [1]doi:10.1192/bjp.107.449.633 Retrieved 2012-01-20
liv.ac.uk
Division of Psychiatry, University of Liverpool, 2nd Floor, Block B, Waterhouse Building, 1-5 Brownlow Street, Liverpool, L69 3GL, UK weblink Retrieved 2012-01-20
rcpsych.org
bjp.rcpsych.org
Karl Leonhard, Professor of Psychiatry and Neurology - Cycloid Psychoses—Endogenous Psychoses which are neither Schizophrenic nor Manic-Depressive The British Journal of Psychiatry (1961) 107: 633-648 [1]doi:10.1192/bjp.107.449.633 Retrieved 2012-01-20
pb.rcpsych.org
R.H.MacMallister rcpsych Retrieved 20 January 2012.