Abdel, Farag, and Salam Attia. “On the Level-Upcrossings of Stochastic Processes”. Anal. Numér. Théor. Approx. 8, no. 2 (August 1, 1979): 127–135. Accessed November 23, 2024. https://ictp.acad.ro/jnaat/journal/article/view/1979-vol8-no2-art2.