Goginava, U. “On the Embedding of Waterman Class in the Class <i>H<sub>p</sub></i><sup>ω</Sup&gt;”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 57, no. 11, Nov. 2005, pp. 1557–1562, https://umj.imath.kiev.ua/index.php/umj/article/view/3707.