Perfect fluid warp drive solutions with the cosmological constant Osvaldo L. Santos-Pereira, Everton M. C. Abreu and Marcelo B. Ribeiro Eur. Phys. J. Plus, 136 9 (2021) 902 Published online: 02 September 2021 DOI: 10.1140/epjp/s13360-021-01899-7