Stress and Self-injurious Behavior; Hormonal and Serotonergic Parameters in Mentally Retarded Subjects - Verhoeven, W M A; Tuinier, S; van den Berg, Y W M M; Coppus, A M W; Fekkes, D; Pepplinkhuizen, L; Thijssen, J H H (Pharmacopsychiatry, 1999)