Orbital variability of the PSR J2051-0827 binary system O. Doroshenko, O. Löhmer, M. Kramer, A. Jessner, R. Wielebinski, A. G. Lyne and Ch. Lange A&A, 379 2 (2001) 579-587 Published online: 15 November 2001 DOI: 10.1051/0004-6361:20011349