Regularization ambiguity and van der Waals black hole in 2 + 1 dimensions Patricio Gaete, Piero Nicolini and Euro Spallucci Eur. Phys. J. C, 81 6 (2021) 526 Published online: 20 June 2021 DOI: 10.1140/epjc/s10052-021-09301-7