Nozari, K., Namdari, S., & Vahedi, J. (2012). Natural Cutoffs and Dynamics of Harmonic Oscillations. Chinese Journal of Physics, 50(4), 554-562. https://www.airitilibrary.com/Article/Detail?DocID=05779073-201208-201210230017-201210230017-554-562
BARTH, K. F., & BRANNAN, D. A. (1996). ASYMPTOTIC TRACTS OF HARMONIC FUNCTIONS III. International Journal of Mathematics and Mathematical Sciences, 1996(), 633-636. https://doi.org/10.1155/S0161171296000890