1. [1] V. Akkermans, F. Font, J. Funollet, B. de Jong, G. Roma, S. Togias, and X. Serra, “FREESOUND 2.0: An Improved Platform for Sharing Audio Clips,” 12th Int. Soc. Music Inf. Retr. Conf., 2011.
2. [2] Music Technology Group of Universitat Pompeu Fabra, “The Freesound Project.,” https://www.freesound.org/ (Retrieved 2020-12-20).
3. [3] SoundCloud Limited, “SoundCloud-Hear the world's sounds,” https://soundcloud.com/ (Retrieved 2020-12-20).
4. [4] F. López, “Environmental sound matter,” 1998. [Online]. Available: http://www.franciscolopez.net/pdf/env.pdf [Accessed: 23-Apr-2021].
5. [5] D. Michael, “Toward a Dark Nature Recording,” Organised Sound, vol.16, no.3, pp.206-210, 2011. 10.1017/s1355771811000203