TPSI2140-Q1: app notes for isolation measurement with V- as reference

Tool/software:

Hi,

My costumer is trying to do calculation for isolation measurement with TPSI2140-Q1 

In the datasheet there are two ways to measure isolation 1. Chassis ground reference and 2. Battery V- reference.

In their system they planned to use Battery V- reference for isolation measurement.

Are there any application notes/documents which implement this method in addition to what mentioned in the datasheet?

Thanks,

Best regards

Oscar