F. Bigolin, F. Serra Cassano: Intrinsic regular graphs in Heisenberg groups vs. weak solutions of non linear first-order PDEs Adv. Calc. Var. (Accepted Paper) 2009 F. Bigolin, F. Serra Cassano: Distributional solutions of Burgers' equation and intrinsic regular graphs in Heisenberg groups JMAA (Accepted Paper) p. 11, 2009 F. Bigolin: Intrinsic regular hypersurfaces in Heisenberg groups and weak solutions of non linear first-order PDEs (Ph.D. Thesis) 2009 F. Bigolin, D. Vittone: Some remarks about parametrizations of intrinsic regular surfaces in the Heisenberg group Publ. Mat. Vol. 54, N. 1, p. 159-172, 2010 F. Bigolin, L. Caravenna, F. Serra Cassano: INTRINSIC LIPSCHITZ GRAPHS IN HEISENBERG GROUPS AND CONTINUOUS SOLUTIONS OF BALANCE EQUATIONS (Preprint) 2012 F. Bigolin: Regularity results for a class of obstacle problems in Heisenberg groups (Submitted Paper) 2012