Poroshin, S. and Usik, V. 2021. SPECIFIC FEATURES OF USING THE FOURTH STAGE OF ACOUSTIC EXPERTISE FOR SPECIAL PURPOSE PREMISES. INNOVATIVE TECHNOLOGIES AND SCIENTIFIC SOLUTIONS FOR INDUSTRIES. 3 (17) (Oct. 2021), 41–61. DOI:https://doi.org/10.30837/ITSSI.2021.17.041.