Hashim, A., and A. Hadi. “Synthesis and Characterization of Novel Piezoelectric and Energy Storage Nanocomposites: Biodegradable Materials–Magnesium Oxide Nanoparticles”. Ukrainian Journal of Physics 62, no. 12 (September 18, 2018): 1050. Accessed February 24, 2020. https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2018243.