A ~4.6 h quasi-periodic oscillation in the BL Lacertae PKS 2155-304?P. Lachowicz, A. C. Gupta, H. Gaur and P. J. WiitaA&A, 506 2 (2009) L17-L20DOI: https://doi.org/10.1051/0004-6361/200913161
