Three-dimensional modified Korteweg-de Vries equation in a magnetised relativistic plasma with positron beam and vortex-like electron distributionRidip Sarma, Apul N. Dev, Birbaishri Boro, Ranjan Das and Nirab C. AdhikaryEur. Phys. J. D, 74 2 (2020) 23DOI: https://doi.org/10.1140/epjd/e2019-100422-y