Sylvestre-Williams, Nicholas, and Ramani Ramakrishnan. “Error Bounds, Uncertainties and Confidence Limits of Outdoor Sound Propagation”. Canadian Acoustics 34, no. 3 (September 1, 2006): 42–43. Accessed July 26, 2021. https://jcaa.caa-aca.ca/index.php/jcaa/article/view/1813.