Beekman AT, Copeland JR, Prince MJ : Review of community prevalence of depression in later life. Br J Psychiatr 174 : 307-311, 1999
Hidaka S, Ikejima C, Kodama C, et al : Prevalence of depression and depressive symptoms among older Japanese people : comorbidity of mild cognitive impairment and depression. Int J Geriatr Psychiatry 27 : 271-279, 2012