Zongbin Chen, “Geometric construction of generators of CoHA of doubled quiver”, Comptes Rendus. Mathématique, 352:12 (2014), 1039
Sergey Mozgovoy, “Motivic Donaldson–Thomas invariants and the Kac conjecture”, Compositio Math., 149:3 (2013), 495
Tamás Hausel, Emmanuel Letellier, Fernando Rodriguez-Villegas, “Positivity for Kac polynomials and DT-invariants of quivers”, Ann. Math., 177:3 (2013), 1147