Belishev, M. “Dynamical Inverse Problem for the Equation ð’°áµ¼áµ¼ âˆ’ Î”ð’° âˆ’ âˆ‡lnðœŒ · âˆ‡ð’° = (the BC Method)”. CUBO, A Mathematical Journal, vol. 10, no. 2, July 2008, pp. 15–30, https://www.perspectivasdelacomunicacion.cl/ojs/index.php/cubo/article/view/1513.