Journal Article
Koyanagi, Ai, Noe Garin, Beatriz Olaya, Jose L Ayuso-Mateos, Somnath Chatterji, Matilde Leonardi, Seppo Koskinen, Beata Tobiasz-Adamczyk, and Josep Maria Haro.
"Chronic Conditions and Sleep Problems among Adults Aged 50 years or over in Nine Countries: A Multi-Country Study." PloS one 9, no. 12 (2014).