Zanello, Fabrizio. “On Bergeron’s Positivity Problem for $q$-Binomial Coefficients”. The Electronic Journal of Combinatorics 25, no. 2 (April 27, 2018): P2.17. Accessed March 27, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v25i2p17.