COMĂNECI A. On Fryszkowski’s problem. Stud. Univ. Babeş-Bolyai Math. [Internet]. 2017 Dec. 30 [cited 2025 Feb. 5];62(4):537–542. Available from: https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/1919