
vdutkiewicz thinks this is interesting:
Take a look now at the right column of Table 14.1. To account for the inflows and outflows of cash, we start by adding back to the net income the noncash charge of depreciation and amortization. Then we subtract the net capital expense, which is the difference between investments in and sales of fixed assets. And then we subtract the increase in net working capital, which are cash contributions to the daytoday operations. (But note that, if a company sells more fixed assets than it invests in, the difference will increase cash flow; and the same will happen if it decreases its net working capital.)
From
 14 Stocks II: The WACC model
 from The Financial Times Guide to Understanding Finance, 2nd Edition
 Publisher: Pearson Business
 Released: May 2011
Note
Description of EFCF