Social relations in older adults: Secular trends and longitudinal changes over a 16-year follow-up.
Lyyra
Tiina-Mari
TM
Gerontology Research Center, PO Box 35 (Viveca), FIN-40014 University of Jyväskylä, Finland. tilyyra@sport.jyu.fi
Lyyra
Anna-Liisa
AL
Lumme-Sandt
Kirsi
K
Tiikkainen
Pirjo
P
Heikkinen
Riitta-Liisa
RL