Non-KAM (Kolmogorov-Arnold-Moser) incommensurate states of the discrete Frenkel-Kontorova chain S.E. Burkov et Ya. G. SinaiJ. Physique Lett., 45 9 (1984) 409-412DOI: https://doi.org/10.1051/jphyslet:01984004509040900
