On epsilon expansions of four-loop non-planar massless propagator diagrams R.N. Lee, A.V. Smirnov and V.A. Smirnov Eur. Phys. J. C, 71 8 (2011) 1708 Published online: 12 August 2011 DOI: 10.1140/epjc/s10052-011-1708-0