Natl. longitudinal study (NSL) of the high school class of 1972. NLS, class of 1972, school file documentation. National longitudinal study of the high school class of 1972. NLS, class of 1972, fifth follow-up. Enlarged fiche for NLS, class of 1972, fifth follow-up codebook
National Center for Education Statistics, National Archive of Computerized Data on Aging (U.S.), Inter-university Consortium for Political and Social Research, 1980