Abell, JG; Shipley, MJ; Ferrie, JE; Kivimäki, M; Kumari, M; (2016) Association of chronic insomnia symptoms and recurrent extreme sleep duration over 10 years with well-being in older adults: a cohort study. BMJ Open , 6 (2) , Article e009501. 10.1136/bmjopen-2015-009501. Green open access