Key points are not available for this paper at this time.
Per Kragh Andersen, , Richard Gill, Niels Keiding, Linear Nonparametric Tests for Comparison of Counting Processes, with Applications to Censored Survival Data, Correspondent Paper, International Statistical Review / Revue Internationale de Statistique, Vol. 50, No. 3 (Dec., 1982), pp. 219-244
Andersen et al. (Wed,) studied this question.