If you are of the value investing philosophy and you also like to invest in companies with growing cash flows, then this article will provide you with four stocks you may want to keep on your radar. To construct this list, we looked for companies that experienced growing free operating cash flow as a portion of revenue:

- TTM FOCF/Revenue > 3yr avg. FOCF/Revenue
- TTM FOCF/Revenue > 3yr avg. FOCF/Revenue

And that were also significantly undervalued by the Graham number, which is calculated as follows:

G. Number = Square Root of (22.5) x (Earnings per Share) x (Book Value per Share)

This equation is predicated on Grahamâ€™s belief that the price-to-earnings (P/EPS) ratio should be no more than 15, and the price-to-book value (P/BVPS) ratio should be no more than 1.5. Therefore, we only included companies that meet both of these criteria. As a result, the product of the two should not be more than 22.5. In other words, (P/EPS of 15) x (P/BVPS of 1.5) = 22.5.

*Interactive Chart: Press Play to compare changes in analyst ratings over the last two years for the stocks mentioned below. Analyst ratings sourced from Zacks Investment Research. *

We also created a price-weighted index of the stocks mentioned below, and monitored the performance of the list relative to the S&P 500 index over the last month. To access a complete analysis of this list's recent performance, click here.

* 1. First Citizens Bancshares Inc. (NASDAQ:FCNCA): *Regional Banks Industry. Market cap of $1.89B. TTM FOCF/Revenue at 23.83% vs. 3-yr average at 13.38% and 5-yr average at 8.12%. BVPS at $171.46, diluted EPS at $14.29. Graham number = sqrt(22.5 x $171.46 x $14.29) = $234.79. Given the current price at $182.25, this implies an upside of 28.83%. The stock has lost 10.59% over the last year.

* 2. Superior Industries International, Inc. (NYSE:SUP): *Auto Parts Industry. Market cap of $538.32M. TTM FOCF/Revenue at 4.69% vs. 3-yr average at 2.72% and 5-yr average at 0.13%. BVPS at $15.66, diluted EPS at $1.89. Graham number = sqrt(22.5 x $15.66 x $1.89) = $25.81. Given the current price at $20.1, this implies an upside of 28.39%. The stock has gained 34.59% over the last year.

* 3. KEMET Corp. (NYSE:KEM): *Diversified Electronics Industry. Market cap of $357.05M. TTM FOCF/Revenue at 7.75% vs. 3-yr average at 1.32% and 5-yr average at 0.61%. BVPS at $9.69, diluted EPS at $1.22. Graham number = sqrt(22.5 x $9.69 x $1.22) = $16.31. Given the current price at $13.12, this implies an upside of 24.31%. The stock has performed poorly over the last month, losing 14.47%.

* 4. CNH Global NV (NYSE:CNH): *Farm & Construction Machinery Industry. Market cap of $8.64B. TTM FOCF/Revenue at 4.89% vs. 3-yr average at 3.4% and 5-yr average at 1.87%. BVPS at $32.17, diluted EPS at $2.45. Graham number = sqrt(22.5 x $32.17 x $2.45) = $42.11. Given the current price at $36.56, this implies an upside of 15.18%. This is a risky stock that is significantly more volatile than the overall market (beta = 2.55). It's been a rough couple of days for the stock, losing 7.6% over the last week.

*Data sourced from Screener.co, Yahoo Finance and Finviz.*

**Disclosure: **I have no positions in any stocks mentioned, and no plans to initiate any positions within the next 72 hours.