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 tried-and-true metrics and fundamental analysis to find companies that they believe are undervalued at their current share price levels.On top of the Zacks Rank, investors can also look at our innovative Style Scores system to find stocks with specific traits. For example, value investors will want to focus on the "Value" category. Stocks with high Zacks Ranks and "A" grades for Value will be some of the highest-quality value stocks on the market today.One stock to keep an eye on is CF Industries (CF). CF is currently sporting a Zacks Rank of #2 (Buy) and an A for Value. The stock has a Forward P/E ratio of 5.75. This compares to its industry's average Forward P/E of 5.77. Over the past year, CF's Forward P/E has been as high as 19.37 and as low as 4.78, with a median of 6.88.Finally, investors should note that CF has a P/CF ratio of 7.76. 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. CF's P/CF compares to its industry's average P/CF of 7.92. Over the past 52 weeks, CF's P/CF has been as high as 13.55 and as low as 6.66, with a median of 8.46.Investors could also keep in mind Nutrien (NTR), an Fertilizers stock with a Zacks Rank of # 2 (Buy) and Value grade of A.Nutrien is trading at a forward earnings multiple of 5.20 at the moment, with a PEG ratio of 0.65. This compares to its industry's average P/E of 5.77 and average PEG ratio of 0.62.Over the last 12 months, NTR's P/E has been as high as 16.42, as low as 4.44, with a median of 8.74, and its PEG ratio has been as high as 2.05, as low as 0.56, with a median of 1.09.Furthermore, Nutrien holds a P/B ratio of 1.87 and its industry's price-to-book ratio is 2.19. NTR's P/B has been as high as 2.58, as low as 1.42, with a median of 1.73 over the past 12 months.Value investors will likely look at more than just these metrics, but the above data helps show that CF Industries and Nutrien are likely undervalued currently. And when considering the strength of its earnings outlook, CF and NTR sticks out as one of the market's strongest value stocks. Just Released: Zacks Top 10 Stocks for 2022 In addition to the investment ideas discussed above, would you like to know about our 10 top picks for the entirety of 2022? From inception in 2012 through 2021, the Zacks Top 10 Stocks portfolios gained an impressive +1,001.2% versus the S&P 500’s +348.7%. Now our Director of Research has combed through 4,000 companies covered by the Zacks Rank and has handpicked the best 10 tickers to buy and hold. Don’t miss your chance to get in…because the sooner you do, the more upside you stand to grab.See Stocks Now >>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 CF Industries Holdings, Inc. (CF): Free Stock Analysis Report Nutrien Ltd. (NTR): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research