Alfarano, Gianira N., Martino Borello, and Alessandro Neri. “Outer Strong Blocking Sets”. The Electronic Journal of Combinatorics 31, no. 2 (April 19, 2024): #P2.18. Accessed April 17, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v31i2p18.