Grigor'yan, Alexander; Saloff-Coste, Laurent
Annales de l'Institut Fourier, Volume 55 (2005) no. 3 p. 825-890
Coulhon, Thierry; Grigor'yan, Alexander; Pittet, Christophe
Annales de l'Institut Fourier, Volume 51 (2001) no. 6 p. 1763-1827
