Gap solitons in Bragg gratings with a harmonic superlattice K. Yagasaki, I. M. Merhasin, B. A. Malomed, T. Wagenknecht and A. R. Champneys Europhys. Lett., 74 6 (2006) 1006-1012 Published online: 12 May 2006 DOI: 10.1209/epl/i2005-10593-0