Koike H, Pellicer D, Raggi M, Wilson S. Flag Bicolorings, Pseudo-Orientations, and Double Covers of Maps. Electron. J. Combin. [Internet]. 2017Jan.20 [cited 2026Jun.6];24(1):#P1.3. Available from: https://www.combinatorics.org/ojs/index.php/eljc/article/view/v24i1p3