TY - JOUR AU - Alessandra Cutrì AU - Nicoletta Tchou TI - Fully nonlinear degenerate operators associated with the Heisenberg group: barrier functions and qualitative properties JO - Comptes Rendus. Mathématique PY - 2007 SP - 559 EP - 563 VL - 344 IS - 9 PB - Elsevier DO - 10.1016/j.crma.2007.03.003 LA - en ID - CRMATH_2007__344_9_559_0 ER -