Halekoh U, Højsgaard S. A Kenward-Roger Approximation and Parametric Bootstrap Methods for Tests in Linear Mixed Models – The R Package pbkrtest. J. Stat. Soft. [Internet]. 2014 Sep. 12 [cited 2024 Apr. 25];59(9):1-32. Available from: https://www.jstatsoft.org/index.php/jss/article/view/v059i09