Hambardzumyan, A.J. “STUDY OF SPECTROSCOPIC PROPERTIES OF LIGNIN BY UV AND FLUORESCENT SPECTROSCOPIC METHODS”. Proceedings of the YSU B: Chemical and Biological Sciences, vol. 46, no. 2 (228), May 2012, pp. 3-7, doi:10.46991/PYSU:B/2012.46.2.003.