Article No. 814
A. M. Samoilenko, Y. V. Teplinsky, and K. V. Pasyuk: A construction of an infinite dimensional invariant torus for a countable system of linear differential-difference equations via the method of reduction in the angular variable. Published in vol. 14 (2011), No. 2, pp. 267-280.
Available in PDFEntire volume 14