http://www.o-a.info/background/pdfs/tuning_the_world_EN.pdf
http://www.hmmh.com/cmsdocuments/urban_soundscape-deb.pdf
http://www.acousticdesign.se/upload/files/Paper%20No%20SS0182%20Acoustic%20Design%20Artifacts%20and%20Methods%20for%20Urban%20Soundscapes.pdf
