“Alcohol and Tobacco Variables in the Assessment of Internal Validity in an Unmatched Case-Control Study of Occupational Cancer in the Campania Region of Italy, 1988-1990”. European Journal of Oncology and Environmental Health, vol. 12, no. 1, Jan. 2017, pp. 15-22, https://mattioli1885journals.com/index.php/EJOEH/article/view/4957.