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23 Oct 1998 / in "III. International Workshop on Classical and Quantum Integrable Systems", L.G. Mardoyan, G.S. Pogosyan and A.N. Sissakian eds., (JINR Publishing, Dubna, 1998) 94-103
16 Sep 1998 / in R. Casalbuoni, R.Giachetti, V.Tognetti, R. Vaia, P.Verrucchi, eds. "Path Integrals from peV to TeV: 50 years after Feynman's paper", (World Scientific, Singapore, 1999) pp. 213-216