Incidence of dementia in a population older than 75 years in the United Kingdom. - Paykel,E.S.; Brayne,C.; Huppert,F.A.; Gill,C.; Barkley,C.; Gehlhaar,E.; Beardsall,L.; Girling,D.M.; Pollitt,P.; O'Connor,D. (Arch Gen Psychiatry, 1994)