Measurement of the Rb D2 transition linewidth at ultralow temperature B. E. Schultz, H. Ming, G. A. Noble and W. A. van Wijngaarden Eur. Phys. J. D, 48 2 (2008) 171-176 Published online: 06 June 2008 DOI: 10.1140/epjd/e2008-00109-0