Cross-cultural aspects of sleep in the elderly.
D000368:Aged; D001315:Australia; D003431:Cross-Cultural Comparison; D005260:Female; D006115:Greece; D006801:Humans; D007558:Italy; D008297:Male; D008800:Mexico; D008875:Middle Aged; D012890:Sleep; D013030:Spain; D014481:United States; D014687:Venezuela