Groen, Ben M. “The Vocalic System in Baudouin De Courtenay’s Opyt Fonetiki rez’janskix Govorov”. Slovene Studies: Journal of the Society of Slovene Studies 9, no. 1 (July 1, 1987): 105–109. Accessed May 6, 2024. https://journals.lib.washington.edu/index.php/ssj/article/view/3689.