Czygrinow, Andrzej, and Vikram Kamat. “Tight Co-Degree Condition for Perfect Matchings in 4-Graphs”. The Electronic Journal of Combinatorics 19, no. 2 (May 21, 2012): P20. Accessed March 27, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v19i2p20.