A weak acceleration effect due to residual gravity in a multiply connected universe B. F. Roukema, S. Bajtlik, M. Biesiada, A. Szaniewska and H. Jurkiewicz A&A, 463 3 (2007) 861-871 Published online: 11 December 2006 DOI: 10.1051/0004-6361:20064979