Columbia subject headings:
Harvard subject headings:
Cities and towns--Puerto Rico--Statistics.
Cities and towns--United States--Statistics
Metropolitan areas--Puerto Rico--Statistics.
Metropolitan areas--United States--Statistics
Puerto Rico--Census, 1990.
Reference works.
United States--Census, 1990.
Princeton subject headings:
Cities and towns--Puerto Rico--Statistics.
Cities and towns--United States--Statistics.
Metropolitan areas--Puerto Rico--Statistics.
Metropolitan areas--United States--Statistics.
Puerto Rico--Census, 1990.
Statistics.
United States--Census, 1990.