Kozubowski, Tomasz J.; Panorska, Anna K.; Podgórski, … - In: Journal of Multivariate Analysis 99 (2008) 7, pp. 1418-1437
The joint distribution of X and N, where N has a geometric distribution and X is the sum of N IID exponential variables (independent of N), is infinitely divisible. This leads to a bivariate Lévy process {(X(t),N(t)),t=0}, whose coordinates are correlated negative binomial and gamma processes....