Here at Zacks, our focus is on the proven Zacks Rank system, which emphasizes earnings estimates and estimate revisions to find great stocks. Nevertheless, we are always paying attention to the latest value, growth, and momentum trends to underscore strong picks.Of these, perhaps no stock market trend is more popular than value investing, which is a strategy that has proven to be successful in all sorts of market environments. Value investors use fundamental analysis and traditional valuation metrics to find stocks that they believe are being undervalued by the market at large.In addition to the Zacks Rank, investors looking for stocks with specific traits can utilize our Style Scores system. Of course, value investors will be most interested in the system's "Value" category. Stocks with "A" grades for Value and high Zacks Ranks are among the best value stocks available at any given moment.One company to watch right now is Telephone & Data Systems (TDS). TDS is currently sporting a Zacks Rank of #1 (Strong Buy), as well as a Value grade of A. The stock is trading with P/E ratio of 16.39 right now. For comparison, its industry sports an average P/E of 19.04. TDS's Forward P/E has been as high as 29.25 and as low as 13.61, with a median of 20.27, all within the past year.Another notable valuation metric for TDS is its P/B ratio of 0.36. Investors use the P/B ratio to look at a stock's market value versus its book value, which is defined as total assets minus total liabilities. This stock's P/B looks solid versus its industry's average P/B of 0.41. Over the past 12 months, TDS's P/B has been as high as 0.54 and as low as 0.32, with a median of 0.42.Finally, our model also underscores that TDS has a P/CF ratio of 1.79. This figure highlights a company's operating cash flow and can be used to find firms that are undervalued when considering their impressive cash outlook. This company's current P/CF looks solid when compared to its industry's average P/CF of 2.07. Over the past year, TDS's P/CF has been as high as 2.80 and as low as 1.68, with a median of 2.17.These are only a few of the key metrics included in Telephone & Data Systems's strong Value grade, but they help show that the stock is likely undervalued right now. When factoring in the strength of its earnings outlook, TDS looks like an impressive value stock at the moment.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Telephone and Data Systems, Inc. (TDS): Free Stock Analysis Report To read this article on Zacks.com click here.