On limiting distribution of U-statistics based on associated random   variables
  Let $\{X_n, n \ge 1\}$ be a sequence of stationary associated random variables. We discuss another set of conditions under which a central limit theorem for U-statistics based on $\{X_n, n \ge 1\}$ holds. We look at U-statistics based on differentiable kernels of degree 2 and above. We also discuss some applications. 
Mansi Garg and Isha Dewan
math.ST stat.TH