We basically followed the idea of buying comapnies selling below working-capital - at two thirds of working-capital.
Before selling, try to re-evaluate the company again and see where the stock sells in realtion to its book value.
Ben was a very simple straightforward man with a brilliant quick mind.
You know, people tend to like to buy companies that are doing well.
Be aware of the level of the stock market. Are yields low and PE ratios high?
I agree with Warren to keep it simple and not use higher mathematics in your analysis.