Mokhnatska, L.V., et al. “Ultrafine Beta-FeOOH and Fe3O4 Obtained by Precipitation Method: Comparative Study of Electrical and Electrochemical Properties”. Physics and Chemistry of Solid State, vol. 21, no. 4, Dec. 2020, pp. 680-8, doi:10.15330/pcss.21.4.680-688.