References for the NRTL method

Renon, H.; Prausnitz, J. M. Local compositions in thermodynamic excess functions for liquid mixtures. AIChE J. 1968, 14 (1), 135-144.

Harris, R. E. DISTILLATION PRACTICES-DISTILLATION DESIGNS USING FLOWTRAN. Chem. Eng. Prog. 1972, 68 (10), 56.