http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Repeated surveys, a technique for asking the same questions to different samples of people, allows researchers to analyse changes in society as a whole. Firebaugh shows how to separate cohort, period and age effects, and model aggregate trends.
Quantitative applications in the social sciences ; v.115