Niemiec, Mateusz. “The Mechanism of Settling Tax on Goods and Services in the Relationship Between the Investor – Main Contractor (buyer of Construction Services) and Another Contractor in the Light of Legal Changes in Force from January 1, 2017”. State and Local Government Budget Law 6, no. 3 (November 21, 2018): 89–113. Accessed July 4, 2025. https://apcz.umk.pl/PBPS/article/view/PBPS.2018.018.