Columbia subject headings:
Labor mobility--Africa, North--Mathematical models.
Labor mobility--Middle East--Mathematical models.
Migration, Internal--Africa, North--Mathematical models.
Migration, Internal--Middle East--Mathematical models.
Harvard subject headings:
Labor mobility--Africa, North--Mathematical models.
Labor mobility--Middle East--Mathematical models.
Migration, Internal--Africa, North--Mathematical models.
Migration, Internal--Middle East--Mathematical models.
Princeton subject headings:
Labor mobility--Africa, North--Mathematical models.
Labor mobility--Middle East--Mathematical models.
Migration, Internal--Africa, North--Mathematical models.
Migration, Internal--Middle East--Mathematical models.