Reference Quality Vapor-Liquid Equilibrium Data for the Binary Systems Methane + Ethane, + Propane, + Butane, and + 2-Methylpropane, at Temperatures from (203 to 273) K and Pressures to 9 MPa May, E.F.; Guo, J.Y.; Oakley, J.H.; Hughes, T.J.; Graham, B.F.; Marsh, K.N.; Huang, S.H.; Journal of Chemical & Engineering Data 2015, 60, 3606-3620