Ceglarska-Jóźwiak, J. 2019. Contractor’s specific problems of social insurance in the context of the lack of the contractor’s obligation to personally provide work. Acta Universitatis Lodziensis. Folia Iuridica. 88, (Sep. 2019), 157–166. DOI:https://doi.org/10.18778/0208-6069.88.14.