[1] Johnson K H . Adv Quantum Chem, 1973, 7: 143
[2] Dill D, Dehmer J L . J Chem Phys, 1974, 61: 692
[3] Kutzler F W, Natoli C R, Misemer D K et al . J Chem Phys, 1980, 73: 3274
[4] Natoli C R, Benfatto M . J Phys (Paris), 1986, C8: 11
[5] Tyson T A, Hodgson K O, Natoli C R et al . Phys Rev, 1992, B46: 5997, and references therein
[6] Lee P A, Pendry J B . Phys Rev, 1975, B11: 2795
[7] Lee P A, Beni G . Phys Rev, 1977, B15: 2862
[8] Benfatto M, Natoli C R, Bianconi A et al . Phys Rev, 1986, B34: 5774
[9] Filipponi A, Di Cicco A, Tyson T A et al . Solid State Commun, 1991, 78: 265
[10] Chou S H, Rehr J J, Stern E A et al . Phys Rev, 1987, B35: 2604
[11] Natoli C R, Benfatto M, Brouder C et al . Phys Rev, 1990, B42: 1944
[12] Benfatto M, Natoli C R, Filipponi A . Phys Rev, 1989, B40: 9626
[13] Benfatto M . Phys, 1995, B208&209: 42
[14] Benfatto M, Della Longa S . J Synchr Radiat, 2001, 8: 1087
[15] Della Longa S, Arcovito A, Girasole M et al . Phys Rev Lett, 2001, 8715(15): 5501
[16] Benfatto M, Felici R . Phys Rev, 2001, B64(11): 11541
