Bandura, A.I., Salo, T.M. and Skaskiv, O.B. 2022. Slice holomorphic functions in the unit ball: boundedness of $L$-index in a direction and related properties. Matematychni Studii. 57, 1 (Mar. 2022), 68-78. DOI:https://doi.org/10.30970/ms.57.1.68-78.