Thermodynamics of mixtures with strongly negative deviations from Raoult's law. XV. Permittivities and refractive indices for 1-alkanol + n -hexylamine systems at (293.15-303.15) K. Application of the Kirkwood-Fröhlich model Hevia, F.; González, J.A.; Cobos, A.; Garcí­a de la Fuente, I.; Alonso-Tristán, C.; Fluid Phase Equilibria 2018, 468, 18-28