1. Odd Hadwiger's conjecture for the complements of Kneser graphs. With Meirun Chen, Lujia Wang, and Sanming Zhou,
  2. Fractional balanced chromatic number of signed subcubic graphs. With Xiaolan Hu, Luis Kuffner, Jiaao Li, Lujia Wang, Zhouningxin Wang, and Xiaowei Yu.
  3. Fractional balanced chromatic number and arboricity of planar (signed) graphs. With Lan Anh Pham, Cyril Pujol, and Huan Zhoun.
  4. Density of 2-critical signed graphs. With Weiqiang Yu.
  5. Colouring signed analogues of Kneser, Schrijver, and Borsuk graphs. With Luis Kuffner, Lujia Wang, Xiaowei Yu, Huan Zhou, and Xuding Zhu.
  6. Signed projective cubes, a homomorphism point of view. With Meirun Chen and Alessandra Sarti.
  7. On core categorical product of (di)graphs. With Cyril Pujol.
  8. Colouring negative exact-distance graphs of signed graphs. With Patrice Ossona de Mendez, Daniel A. Quiroz, Robert Šámal, Weiqiang Yu.
  9. Critically 3-frustrated signed graphs-II. With C. Cappello, E. Steffen, and Z. Wang.
  10. Balanced-chromatic number and Hadwiger-like conjectures.' With Andrea Jimenez, Jessica McDonald, Kathryn Nurse, and Daniel A. Quiroz.
  11. Winding number and circular 4-coloring of signed graphs.
  12. Cliques in exact distance powers of graphs of given maximum degree, with F. Foucaud, S. Mishra, N. Narayanan, P. Valicov.
  13. On powers of interval graphs and their orders. With F. Foucaud, A. Parreau, P. Valicov.
  14. On orthogonality graphs, with M. DeVos, M. Gheble, L. Goddyn, B. Mohar.
  15. Complexity of planar homomorphisms, with P. Hell, C. Tardif. We prove that $C_{2k+1}$-coloirng of planar graphs is NP-Complete. This is also proved with a different technique by G. MacGillivray and M. Siggers. Furthermore, we propose that perhaps H-coloring of planar graphs is NP-complete if H is a planar core but not isomorphic to $K_1, K_2, K_4$.
  16. Edge-Choosability of the Petersen Graph, with P. Haxell. Answering a question of B. Mohar we show that the multigraph obtained from the Petersen graph with each edge being replaced by k parallel edges is $3k$-choosable if and only if $k$ is an even number.
  17. Two conjectures on the list coloring number, with P. Haxell. We give a stronger reformulation of Reed's conjecture on list coloring number. The original conjecture was disproved by T. Bohman, R. Holzman, where Reed himself proved that his conjecture asymptotically is correct. With our re-formulation of the conjecture disproving the original claim becomes obvious.