Regi, Mauro, Alfredo Del Corpo, and Marcello De Lauretis. “The Use of the Empirical Mode Decomposition for the Identification of Mean Field Aligned Reference Frames”. Annals of Geophysics 59, no. 6 (January 7, 2017): G0651. Accessed September 20, 2021. https://www.annalsofgeophysics.eu/index.php/annals/article/view/7067.