Smoking and alcohol abuse – predictive factors in oropharyngeal squamous cell carcinoma: A retrospective studyAndrejs Lifsics, Elza Rate, Juris Tars, Modra Murovska and Valerija GromaSHS Web Conf., 68 (2019) 02013DOI: https://doi.org/10.1051/shsconf/20196802013