Duality between k-essence and Rastall gravity Kirill A. Bronnikov, Júlio C. Fabris, Oliver F. Piattella, Denis C. Rodrigues and Edison C. Santos Eur. Phys. J. C, 77 6 (2017) 409 Published online: 17 June 2017 DOI: 10.1140/epjc/s10052-017-4977-4