Gadylshin K, Protasov M. Calculation of exact frequency-dependent rays when the solution of the Helmholtz equation is known. Num. Meth. Prog. [Internet]. 2015 Oct. 14 [cited 2024 Apr. 27];16(46):586-94. Available from: https://en.num-meth.ru/index.php/journal/article/view/861