A transient variable 6 Hz QPO from GX 339-4 E. Nespoli, T. Belloni, J. Homan, J. M. Miller, W. H. G Lewin, M. Méndez and M. van der Klis A&A, 412 1 (2003) 235-240 Published online: 25 November 2003 DOI: 10.1051/0004-6361:20031423