V. Póka and B. Gyenge, “Regional impact during covid times on e-grocery industry. Investigation of results Miskolc and Zalaegerszeg and their agglomeration”, Studia Mundi – Economica, vol. 9, no. 3, pp. 30–42, Sep. 2022, doi: 10.18531/Studia.Mundi.2022.09.03.30-42.