Kharchenko, A.Y., Romakh, M.A., Yanova, K.V., Tereshchuk, M.N. and Mchedlov-Petrossyan, N.O. 2019. Aqueous solution of poly (hexamethylene guanidine hydrochloride) and poly (diethylenamine guanidine hydrochloride) as studied with acid-base indicators. Kharkiv University Bulletin. Chemical Series. 33 (Dec. 2019), 65-76. DOI:https://doi.org/10.26565/2220-637X-2019-33-05.