Media 1: Counterpropagating nematicons in bias-free liquid crystals IzdebskayaYana V. ShvedovVlad G. DesyatnikovAnton S. KrolikowskiWieslaw Z. BelićMilivoj AssantoGaetano KivsharYuri S. 2010 Originally published in Optics Express on 15 February 2010 (oe-18-4-3258)