Crstici, B., and O. Lipovan. “A Probabilistic Approach to the Integrability Concept”.
Anal. Numér. Théor. Approx.
17, no. 2 (August 1, 1988): 93–98. Accessed April 11, 2025.
https://ictp.acad.ro/jnaat/journal/article/view/1988-vol17-no2-art1
.