Return back of the extraordinary beam for oblique incidence in helical liquid crystals with large pitchE. V. Aksenova, A. A. Karetnikov, A. P. Kovshik, V. P. Romanov and A. Yu. Val'kovEurophys. Lett., 69 1 (2005) 68-74DOI: https://doi.org/10.1209/epl/i2004-10311-6