10 Nov 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.19-21
29 Dec 2002 / A chapter in Modern Topics in Chemical Physics, ed. by T.F.George, X.Sun and G.P.Zhang, Research Signpost, Trivandrum, India, 2002, pp. 163-182