Here at Zacks, we focus on our proven ranking system, which places an emphasis on earnings estimates and estimate revisions, to find winning stocks. But we also understand that investors develop their own strategies, so we are constantly looking at the latest trends in value, growth, and momentum to find strong companies for our readers.

Considering these trends, value investing is clearly one of the most preferred ways to find strong stocks in any type of market. Value investors use tried-and-true metrics and fundamental analysis to find companies that they believe are undervalued at their current share price levels.

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 value investors might notice is Vista Oil & Gas (VIST Quick QuoteVIST - Free Report) . VIST is currently sporting a Zacks Rank of #1 (Strong Buy) and an A for Value. The stock is trading with a P/E ratio of 3.18, which compares to its industry's average of 6.22. VIST's Forward P/E has been as high as 20.44 and as low as 2.83, with a median of 4.22, all within the past year.

Finally, our model also underscores that VIST has a P/CF ratio of 3.16. This metric focuses on a firm's operating cash flow and is often used to find stocks that are undervalued based on the strength of their cash outlook. This stock's P/CF looks attractive against its industry's average P/CF of 5.05. Within the past 12 months, VIST's P/CF has been as high as 3.65 and as low as 1.63, with a median of 2.75.

Investors could also keep in mind YPF Sociedad Anonima (YPF Quick QuoteYPF - Free Report) , an Oil and Gas - Integrated - International stock with a Zacks Rank of # 1 (Strong Buy) and Value grade of A.

YPF Sociedad Anonima sports a P/B ratio of 0.27 as well; this compares to its industry's price-to-book ratio of 1.41. In the past 52 weeks, YPF's P/B has been as high as 0.29, as low as 0.11, with a median of 0.20.

Value investors will likely look at more than just these metrics, but the above data helps show that Vista Oil & Gas and YPF Sociedad Anonima are likely undervalued currently. And when considering the strength of its earnings outlook, VIST and YPF sticks out as one of the market's strongest value stocks.