Key points are not available for this paper at this time.
Stuart R. Lipsitz, Keith B. G. Dear, Lueping Zhao, Jackknife Estimators of Variance for Parameter Estimates from Estimating Equations with Applications to Clustered Survival Data, Biometrics, Vol. 50, No. 3 (Sep., 1994), pp. 842-846
Lipsitz et al. (Thu,) studied this question.