Equivalent mutants detection is one of biggest obstacles for practical usage of mutation testing. The effort needed to check if mutants are equivalent or not can be very high even for small programs. A systematic literature review of a wide range of approaches to overcome the Equivalent Mutant Problem identified 17 relevant techniques (in 22 articles) and three categories of techniques: detecting (DEM); suggesting (SEM); and avoiding equivalent mutant generation (AEMG). The experiment indicated that Higher Order Mutation in general and JudyDiffOp strategy in particular provide a promising approach to the Equivalent Mutant Problem.