Laroche, C., M. Hodgson, L. Ritmiller, and S. Forshaw. “Audibility of Signals and Alarms in a Coast Guard Environment”. Canadian Acoustics, vol. 27, no. 3, Sept. 1999, pp. 114-5, https://jcaa.caa-aca.ca/index.php/jcaa/article/view/1244.