Thermodynamics of amide + ketone mixtures. 1. Volumetric, speed of sound and refractive index data for N,N-dimethylformamide + 2-alkanone systems at several temperatures Cobos, A.; Hevia, F.; González, J.A.; García De La Fuente, I.; Alonso Tristán, C.; The Journal of Chemical Thermodynamics 2016, 98, 21-32