See Emura, Lin and Wang (2010) <doi:10.1016/j.csda.2010.03.013> for details.
A more general reference for the copula-based analysis of bivariate survival data is

Title: Analysis of Bivariate Survival Data Based on Copulas
Description: Simulating bivariate survival data from copula models.
Estimation of the association parameter in copula models.

Title: Copula-Based Regression Models for Bivariate Censored Data
Description: Copula-based regression models for bivariate censored data, including
bivariate right-censored data and bivariate interval-censored data. Currently
supports Clayton, Gumbel, Frank, Joe, AMH and Copula2 copula models. For
marginal models, it supports parametric (Weibull, Loglogistic, Gompertz),
weakly-parametric piecewise-constant hazards (only for bivariate right-censored)
and semiparametric transformation (only for bivariate interval-censored data)
models. Includes methods for convenient prediction and plotting. Also provides
a bivariate time-to-event simulation function. Method details can be found in
Imports: copula, corpcor, flexsurv, icenReg, magrittr, plotly, pracma,

Imports: caret, copula, corpcor, flexsurv, icenReg, magrittr, plotly,

marginal models, it supports parametric (Weibull, Loglogistic, Gompertz) and
semiparametric (Cox and transformation) models. Includes methods for convenient
prediction and plotting. Also provides a bivariate time-to-event simulation function.
Method details can be found in Sun et.al. (2018) < doi:10.1007/s10985-018-09459-5>

Method details can be found in Sun et.al (2019) Lifetime Data Analysis

Title: Copula-Based Regression Models for Multivariate Censored Data
Description: Copula-based regression models for multivariate censored data, including
bivariate right-censored data, bivariate interval-censored data, and interval-censored
semi-competing risks data. Currently supports Clayton, Gumbel, Frank, Joe, AMH and
Copula2 copula models. For marginal models, it supports parametric (Weibull, Loglogistic,
Gompertz) and semiparametric (Cox and transformation) models. Includes methods for
convenient prediction and plotting. Also provides a bivariate time-to-event simulation
function. Method details can be found in Sun et.al (2019) Lifetime Data Analysis,
Sun et.al (2021) Biostatistics, and Sun et.al (2022) Statistical Methods in Medical