1592952530000 1312632483000 term-1981 1616540943542 1312632486000 1615829356520 adlib fitz-online adlib-term-1981 bb2c701a-e39c-3375-aaf0-9d7bd926ca4b 2 1 differences, class differences, class term reference term-1983 adlib-term-1983 d08e78b5-047c-3830-ae0d-941e94005df1 social stratification