Columbia subject headings:
Homeless persons--Research--United States--Congresses.
Homeless persons--Substance use--Research--United States--Congresses.
Mentally ill--Research--United States--Congresses.
Harvard subject headings:
Homeless persons--Mental health--Research--United States--Congresses.
Homeless persons--Substance use--Research--United States--Congresses.
Mentally ill--Research--United States--Congresses.
Princeton subject headings: