Oláh , J. ., J. . Popp, D. . Máté, and Y. . Ardhi Hidayat. “Market Structure and Concentration Ratio: Evidence of IT Companies in Hungary”. Forum Scientiae Oeconomia, vol. 7, no. 3, Sept. 2019, pp. 7-18, doi:10.23762/FSO_VOL7_NO3_1.