Genys, Jonas, Renata Macaitienė, Santa Račkauskienė, and Darius Šiaučiūnas. “A Mixed Joint Universality Theorem for zeta‐functions”. Mathematical Modelling and Analysis 15, no. 4 (November 15, 2010): 431-446. Accessed September 25, 2020. https://journals.vgtu.lt/index.php/MMA/article/view/6034.