Kharkale, S. S.; Bhuyar, S. S.; Gaidhane, M. K. ACOUSTICAL STUDIES OF COPOLYMER OF P-HYDROXY BENZOIC ACID AND FORMALDEHYDE IN N, N-DIMETHYL FORMAMIDE AND DIMETHYL SULFOXIDE BY ULTRASONIC VELOCITY MEASUREMENTS. Int J Curr Pharm Sci 2015, 7, 62-65.