Drasovean, R., and S. Condurache-Bota. “Correlation Studies Between Sol Aging Time and Substrate Dipping Time Parameter and Optical Properties of Cobalt Oxide Layers”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 25, no. 1, Jan. 2016, pp. 17-25, https://www.gssrr.org/index.php/JournalOfBasicAndApplied/article/view/5051.