The reference publication for the CS-NPSA program package :

Rabin Dhakal, Reed Nieman, Daniel C.A. Valente, Thiago M. Cardozo, Bhumika Jayee, Amna Aqdas, Wenjing Peng, Adelia J.A. Aquino, Yehia Mechref, Hans Lischka, Hanna Moussa, A general new method for calculating the molecular nonpolar surface for analysis of LC-MS data, International Journal of Mass Spectrometry, Volume 461, 2021, 116495, https://doi.org/10.1016/j.ijms.2020.116495