@techreport{Plewis2004,
author = {Plewis, I. and Calderwood, L. and Hawkes, D. and Nathan, G.},
title= {National Child Development Study and 1970 British Cohort Study technical report: Changes in the NCDS and BCS70 populations and samples over time},
year = {2004},
publisher = {University of London, Institute of Education, Centre for Longitudinal Studies},
address = {London},
number = {39 pp.},
}