title: Migrations as a demographic phenomenon.
abstract: "A general introduction to migration theory is presented.  The author distinguishes international and internal migration and considers the implications of this distinction for demographic and geographical studies.  Two main functions of migration are also examined:  the territorial redistribution of demographic characteristics and the time regulation of incentives to marry or child-spacing in the family of migrants."  Polish data are used to suggest appropriate models for the study of migration.
authors.forename: A
authors.initials: A
authors.lastname: Jagielski
mesh_terms: D001721:Birth Intervals; D003710:Demography; D019049:Developed Countries; D004641:Emigration and Immigration; D005060:Europe; D005061:Europe, Eastern; D005193:Family Planning Services; D008393:Marriage; D008962:Models, Theoretical; D011044:Poland; D011153:Population; D011154:Population Characteristics; D011157:Population Dynamics; D012106:Research; D013997:Time Factors
keywords: Birth Spacing; Demographic Factors; Developed Countries; Eastern Europe; Europe; Family Planning; Marriage; Migration; Models, Theoretical; Nuptiality; Poland; Population; Population Characteristics; Population Dynamics; Research Methodology; Theoretical Studies; Time Factors