@techreport{Bethel2005,
author = {Bethel, J. and Green, J.L. and Nord, C. and Kalton, G. and West, J.},
title= {Early Childhood Longitudinal Study, Birth Cohort (ECLS-B): Methodology report for the 9-month data collection (2001-02): Vol. 2. Sampling},
year = {2005},
publisher = {National Center for Education Statistics},
address = {Washington D.C.},
}