VSR symmetries in the DKP algebra: The interplay between Dirac and Elko spinor fields R. T. Cavalcanti, J. M. Hoff da Silva and Roldão da Rocha Eur. Phys. J. Plus, 129 11 (2014) 246 Published online: 13 November 2014 DOI: 10.1140/epjp/i2014-14246-4