DeVos, Matt, and Kathryn Nurse. “A Short Proof of Seymour’s 6-Flow Theorem”. The Electronic Journal of Combinatorics 32, no. 4 (October 17, 2025): #P4.13. Accessed May 30, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v32i4p13.