Under the discrete time risk model with constant interest, SUN Li-juan and GU Lan (2002) have discussed some ruin problems which are about the distributions of the surplus immediately before ruin and the time of the severity of ruin.

• 孙立娟、顾岚(2002)则在具有常利息率的离散时间模型下，讨论了破产前盈余分布、破产持续时间分布的问题。