I. E. Simonov, “A Sharp Markov Brothers-Type Inequality in the Spaces $L_\infty$ and $L_1$ on the Segment”, Mat. Zametki, 93:4 (2013), 604–613; Math. Notes, 93:4 (2013), 607–615
I. E. Simonov, “Sharp Markov brothers type inequality in the spaces $L_p$, $L_1$ on a closed interval”, Trudy Inst. Mat. i Mekh. UrO RAN, 17:3 (2011), 282–290