Here are entered works on migration across national borders in modern times. Works on the movement of population within the borders of a single country are entered under Migration, Internal. Works on the spread of population, largely in prehistoric times, are entered under Human beings--Migrations. Works on the mass migrations of peoples are entered under Migrations of nations. --subdivision Emigration and immigration under names of countries, cities, etc. for works on migration across national borders from a particular place, and/or migration across national borders to a particular place
Here are entered works which discuss the social or demographic aspects of emigrants' return to their country of origin. Works which discuss the legal or administrative aspects of returning to a country of origin are entered under Repatriation.
Here are entered works on population shifts from a rural to an urban environment. Works on population shifts from an urban to a rural environment are entered under Urban-rural migration.
Here are entered works on population shifts from an urban to a rural environment. Works on population shifts from a rural to an urban environment are entered under Rural-urban migration.
--subdivision Vertical distribution under individual animals and groups of animals and individual plants and groups of plants, e.g. Fishes--Vertical distribution; Phytoplankton--Vertical distribution
