Babenko, V.F. and Zhiganova, G.S. (2008) “On the best L2 -approximations of functions by using wavelets”, Ukrains’kyi Matematychnyi Zhurnal, 60(8), pp. 1119 – 1127. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/3229 (Accessed: 6 December 2025).