D. Ghosh and D. Y. Lin, Biometrics 56(2), 554–562 (June 2000), DOI doi.org/10.1111/j.0006-341x.2000.00554.x . Primary byline and abstract: mean frequency is the marginal mean cumulative number of recurrent events in the presence of a terminal event such as death; nonparametric estimation, covariance, simulation and a cancer-trial application.
Publisher author page: onlinelibrary.wiley.com/doi/abs/10.1111/j.0006-341X.2000.00554.x . It spells the first author Debashis Ghosh and identifies D. Y. Lin as corresponding author. The journal issue is June 2000; the publisher page separately lists online publication on 24 May 2004. The online date does not replace the original journal year.