A. Garg, Tunnel splittings for one-dimensional potential wells revisited, American Journal of Physics, vol.68, issue.5, p.430, 2000.
DOI : 10.1119/1.19458
URL : http://arxiv.org/abs/cond-mat/0003115

M. Reed and S. B. , of Methods of modern mathematical physics, Analysis of operators, vol.4, 1978.