1. Ballard [Electronic resource], https://www.ballard.com/ (circulation date 03.04.2023).
2. SGL Carbon [Electronic resource], https://www.sglcarbon.com/en/ (circulation date 03.04.2023).
3. TORAY [Electronic resource], https://www.toray.com/global/ (circulation date 03.04.2023).
4. V.A. Lysenko, M.V. Kriskovets, and S.V. Burinskii, Fibre Chemistry, 51, No. 5, 350−356 (2020).
5. V.A. Lysenko and M.V. Kriskovets, Fibre Chemistry, 53, No. 4, 258−262 (2021).