The (p,ρ,T,x) properties for (x1 n-butane + x2 isobutane) with x1 = (0.2625, 0.4913, and 0.7508) in the temperature range from (280 to 440) K at pressures from (1 to 200) MPa Miyamoto, H.; Koshi, T.; Uematsu, M.; The Journal of Chemical Thermodynamics 2008, 40, 567-572