Vapour-liquid equilibrium of propionic acid + caproic acid, isobutyric acid + caproic acid, valeric acid + caproic acid and caproic acid + enanthoic acid binary mixtures Hlengwere, A.; Iwarere, S.A.; Naidoo, P.; Raal, J.D.; Ramjugernath, D.; Fluid Phase Equilibria 2014, 375, 201-208