1. A contribution to the theory of stochastic processes;Cramér;Proc. Second Berkeley Symp. Math. Statist. Probab.,1951
2. On some classes of nonstationary stochastic processes;Cramér;Proc. Fourth Berkeley Symp. Math. Statist. Proab.,1961
3. Bimeasures and nonstationary processes;Chang,1986
4. Doubly Stochastic Poisson Processes;Grandell,1976