Mair P, Groenen PJF, de Leeuw J. More on Multidimensional Scaling and Unfolding in R: smacof Version 2. J. Stat. Soft. [Internet]. 2022 May 13 [cited 2024 Nov. 24];102(10):1-47. Available from: https://www.jstatsoft.org/index.php/jss/article/view/v102i10