Ulrich, N., Tang, M., Pellegrino, F., Dediu, D., 2021, "Identifying the Russian voiceless non-palatalized fricatives /f/, /s/, and /ʃ/ from acoustic cues using machine learning", The Journal of the Acoustical Society of America, 150:3, pp. 1806-1820 (doi.org/10.1121/10.0005950)