Kopaliani, T. S. “Littlewood - Paley Theorem on $L^{p(t)}(\mathbb{R}^n)$ Spaces”. Ukrains’kyi Matematychnyi Zhurnal 60, no. 12 (December 25, 2008): 1709 – 1715. Accessed December 5, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/3283.