Huron, D., and M. Davis. “The Harmonic Minor Scale Provides an Optimum Way of Reducing Average Melodic Interval Size, Consistent With Sad Affect Cues”. Empirical Musicology Review, vol. 7, no. 3-4, July 2013, pp. 103-17, https://www.osu.tests.sfulib4.publicknowledgeproject.org/index.php/EMR/article/view/3732.