ISO 717-1. Acoustics - Rating of sound insulation in buildings and of building elements - Part 1 : Airborne sound insulation. 1996
ISO 717-2. Acoustics - Rating of sound insulation in buildings and of building elements - Part 2 : Impact sound insulation. 1996
KOYASU, M. Comparison of single-number indices for assessment of sound insulation of building walls based on psychoacoustic experiment. Proc.13th ICA. 1989, 115-118