TACHEV G. On two modified Phillips operators: Dedicated to Professor Heiner Gonska on the occasion of his 70th anniversary. Stud. Univ. Babeş-Bolyai Math. [Internet]. 2019 Sep. 30 [cited 2025 Apr. 20];64(3):305–312. Available from: https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/2295