Keryan, K.A. “AN EXAMPLE OF DOUBLE FOURIER–HAAR SERIES WITH A NONREGULAR SUBSERIES”. Proceedings of the YSU A: Physical and Mathematical Sciences 51, no. 1 (242) (March 20, 2017): 18–21. Accessed July 3, 2024. https://journals.ysu.am/index.php/proceedings-phys-math/article/view/vol51_no1_2017_pp018-021.