The phase of the radio and X-ray pulses of PSR B1937+21 G. Cusumano, W. Hermsen, M. Kramer, L. Kuiper, O. Löhmer, E. Massaro, T. Mineo, L. Nicastro and B. W. Stappers A&A, 410 2 (2003) L9-L12 Published online: 17 November 2003 DOI: 10.1051/0004-6361:20031368