@suru27 Thanks Saurabh. Agree that SSGR is a good proxy for estimating sustainable growth opportunity. Frankly speaking, I found its formula complicated and intimidating 
In any case, the file calculates metrics like Cash Flow from financing activities/Cash flow from Operations, Debt/PAT, Equity Dilution, Historical sales growth, Historical profit growth etc and assigns weights to all of them to understand the business viability. I believe collectively these metrics take care of the sustainable growth aspect.
@nitinjain9282 Thanks Nitin The following links would be good to start with I suggest -
http://forum.valuepickr.com/t/great-articles-to-read-on-the-web/6765/21