Vijapure, Y. . “Synthesis And Properties of Ho+3 Doped Co-Cr-Fe Ferrite Nanoparticles Prepared by Sol-Gel Chemical Route”. International Journal for Research in Applied Sciences and Biotechnology, vol. 9, no. 1, Jan. 2022, pp. 203-6, https://ijrasb.com/index.php/ijrasb/article/view/432.