Chudnovsky, Maria, Tung Nguyen, Alex Scott, and Paul Seymour. “The Vertex Sets of Subtrees of a Tree”. The Electronic Journal of Combinatorics 33, no. 2 (April 14, 2026): #P2.7. Accessed April 18, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v33i2p7.