Nordic basis of calculation of sound insulation in buildings (NT TR 425) Posted onDecember 17, 1997July 17, 2020Author Report #: NT TR 425 Approved: December 1997 Author(s): Dan Brøsted Pedersen, Christian Simmons, Herold Olsen, Pekka Sipari, Steindór Gudmundsson Download pdf Size: 525.64 KB