You will have to find social science journal articles and/or books that have conducted an empirical research study. That is, at least four of the articles you cite must be based on an empirical analysis of qualitative data (interviews or direct observations, including ethnography) or quantitative data (survey data or other statistics). This means you cannot use a textbook or purely theoretical or a literature review-based article or book for your four sources. You can use such articles in addition to your four sources, but you must have four sources that analyze data. minimum of four sources need to be academic sources – that is, journal articles or books. No need for tables and figures.
Book used in university is: Edgell, Stephen. 2006. The Sociology of Work: Continuity and Change in Paid and Unpaid Work, 2nd edition, London: SAGE