Search Results Use the search box below to revise your search, or start a new search. Studies (1) Variables Publications Your query returned 1 studies. Series results are grouped under the most relevant study. Ungroup series results to view all results. Sort by: Title A-Z Released/Updated Time Period Most Cited in ICPSR Bib. 1. Longitudinal Study of the Second Generation in Spain (ILSEG) (ICPSR 36286) Portes, Alejandro; Aparicio, Rosa; Haller, William; et al.