1 "Fișier:Collected_papers_on_acoustics_(IA_collectedpaperso00sabi).pdf".

Fișier:Collected papers on acoustics (IA collectedpaperso00sabi).pdf

sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:Collected_papers_on_acoustics_(IA_collectedpaperso00sabi).pdf...