Investors interested in stocks from the Oil and Gas - Integrated - United States sector have probably already heard of ConocoPhillips (COP) and Cactus, Inc. (WHD) . But which of these two stocks is more attractive to value investors? We'll need to take a closer look to find out.There are plenty of strategies for discovering value stocks, but we have found that pairing a strong Zacks Rank with an impressive grade in the Value category of our Style Scores system produces the best returns. The proven Zacks Ran ...