On a Measure of Tail Asymmetry for the Bivariate Skew-Normal Copula. - Toshinao Yoshiba; Takaaki Koike; Shogo Kato (Symmetry, 2023)

Comparison of correlation-based measures of concordance in terms of asymptotic variance. - Takaaki Koike; Marius Hofert (J. Multivar. Anal., 2024)

Invariant correlation under marginal transforms. - Takaaki Koike; Liyuan Lin; Ruodu Wang (J. Multivar. Anal., 2024)

Joint Mixability and Notions of Negative Dependence. - Takaaki Koike; Liyuan Lin; Ruodu Wang (Math. Oper. Res., 2024)

Measuring and testing tail equivalence. - Takaaki Koike; Shogo Kato; Toshinao Yoshiba (J. Multivar. Anal., 2025)