Peterson LE. COVAR: Computer Program for Multifactor Relative Risks and Tests of Hypotheses Using a Variance-Covariance Matrix from Linear and Log-Linear Regression. J. Stat. Soft. [Internet]. 1997 Nov. 3 [cited 2024 Nov. 21];2(4):1-21. Available from: https://www.jstatsoft.org/index.php/jss/article/view/v002i04