Performance and Emissions Comparison between Biomethane and Natural Gas Fuel in Passenger Vehicles: results of the second testing campaignFabio Cignini, Antonino Genovese, Fernando Ortenzi, Stefano Valentini and Alberto CaprioliE3S Web Conf., 312 (2021) 07019DOI: https://doi.org/10.1051/e3sconf/202131207019