Nalbandyan, M.A. “ON ONE SPECTRUM OF UNIVERSALITY FOR WALSH SYSTEM”. Proceedings of the YSU A: Physical and Mathematical Sciences 46, no. 2 (228) (May 10, 2012): 22–28. Accessed July 22, 2024. https://journals.ysu.am/index.php/proceedings-phys-math/article/view/vol46_no2_2012_pp022-028.