Hart J F
J Geog. 1986 Sep-Oct;85(5):201-11. doi: 10.1080/00221348608979029.
"This paper explores four selected facets of the geography of population in the [U.S.] Midwest that are related to the movement of people: (1) the spread of occupance across the land; (2) the growth of the population of counties once they had been occupied; (3) the distribution of the foreign-born population; and (4) the distribution of retired people who have migrated after they have retired."
(1)居住在这片土地上的人口分布;(2)各县有人居住后的人口增长情况;(3)外国出生人口的分布;以及(4)退休后迁移的退休人员的分布。