@techreport{National Opinion Research Center2007,
author = {National Opinion Research Center},
title= {Appendix A - Sampling design and weighting},
year = {2007},
URL = {http://publicdata.norc.org:41000/gss/Documents/Codebook/A.pdf},
note = {In: General Social Surveys, 1972-2006: Cumulative codebook. Chicago: National Opinion Research Center},
}