[1] Ambrosetti A, Rabinowitz P H. Dual variational methods in critical point theory and applications. J Funct Anal, 1973, 14: 349–381

[2] Bartsch T, Li S J. Critical point theory for asymptotically quadratic functionals and applications to problems with resonance. Nonl Anal, 1997, 28: 419–441

[3] Biroli M, Mataloni S. Stability results for Mountain Pass and Linking type solutions of semilinear problems involving Dirichlet forms. Nonlinear Differ Equ Appl, 2005, 12: 295–321

[4] Biroli M, Mosco U. Sobolev and isoperimetric inequalities for Dirichlet forms on homogeneous spaces. Rend Acc Naz Lincei, 1995, 9: 37–44

[5] Biroli M, Mosco U. Sobolev inequalities on homogeneous spaces. Potential Anal, 1995, 4: 311–324

[6] Biroli M, Tchou N A. Asymptotic behaviour of relaxed Dirichlet problems involving a Dirichlet-Poincaré form. J Anal Appl, 1997, 16(2): 281–309

[7] Biroli M, Tersian S. On the existence of nontrivial solutions to a semilinear equation relative to a Dirichlet form. Ist Lomb (Rend Sci) A, 1997, 131: 151–168

[8] Chang K C. Solutions of asymptotic linear operator equations via Morse theory. Comm Pure Appl Math, 1981, 34: 693–712

[9] Chang K C. Infnite Dimensional Morse Theory and Multiple Solution Problem. Boston: Birkhäuser, 1993

[10] Falconer K. Semilinear partial differential equations on self-similar fractals. Comm Math Phys, 1999, 206: 235–245

[11] Falconer K, Hu J. Nonlinear elliptical equations on the Sierpinski gasket. J Math Anal Appl, 1999, 240: 552–573

[12] Fukushima M, Shima T. On a spectral analysis for the Sierpinski Gasket. Potential Anal, 1992, (1): 1–35

[13] Jacob N,Moroz V. On the semilinear Dirichlet problems for a class of nonlocal operators generating Dirichlet forms//Recent trends in nonlinear analysis. Prog Nonlinear Diff Eq Appl. Birkhäuser, 2000

[14] Liu J Q. A Morse index for a saddle point. Syst Sc Math Sc, 1989, 2: 32–39

[15] Matzeu M. Mountain pass and Linking type solutions for semilinear Dirichlet forms. Progr in Non Diff Eq and Appl, 2000, 40: 217–231

[16] Mawhin J, Willem M. Critical Point Theory and Hamiltonian Systems. Berlin: Springer, 1989

[17] Mosco U. Spectral properties of fractal structures. Rend Accad Naz Lincei (to appear)

[18] Mosco U. Variational metrics on selfsimilar fractals. C R Acad Sci Paris, 1995, 321: 715–720

[19] Wang Z Q. On a superlinear elliptic equation. Ann Inst H Poincar´e Anal Non Linéaire, 1991, 8: 43–57