R. F. Shamoyan, “On some extremal problems in certain harmonic function spaces of several variables related to mixed norm spaces”, Пробл. анал. Issues Anal., 2(20):1 (2013), 43–58
Miloš Arsenović, Romi F. Shamoyan, “Sharp theorems on multipliers and distances in harmonic function spaces in higher dimension”, Журн. СФУ. Сер. Матем. и физ., 5:3 (2012), 291–302