Tikk, Domonkos, and Zoltán Alexin. “Topic and Language Specific Internet Search Engine”. Acta Cybernetica 18, no. 2 (January 1, 2007): 275–291. Accessed April 2, 2025. https://cyber.bibl.u-szeged.hu/index.php/actcybern/article/view/3718.