Shaffer, K., E. Vasiete, B. Jacquez, A. Davis, D. Escalante, C. Hicks, J. McCann, C. Noufi, and P. Salminen. “A Cluster Analysis of Harmony in the McGill Billboard Dataset”. Empirical Musicology Review, vol. 14, no. 3-4, July 2020, pp. 146-62, https://www.osu.tests.sfulib4.publicknowledgeproject.org/index.php/EMR/article/view/5576.