Columbia subject headings:
Middle age--Care and hygiene.
Middle age--Family relationships.
Middle age--Psychological aspects.
Middle-aged persons--Sexual behavior.
Harvard subject headings:
Middle-aged persons--Family relationships.
Middle-aged persons--Health and hygiene.
Middle-aged persons--Psychology.
Middle-aged persons--Sexual behavior.
Princeton subject headings:
Middle age--Care and hygiene.
Middle age--Family relationships.
Middle age--Psychological aspects.
Middle-aged persons--Sexual behavior.