A 10-h period revealed in optical spectra of the highly variable WN8 Wolf-Rayet star WR 123 A.-N. Chené, C. Foellmi, S. V. Marchenko, N. St-Louis, A. F. J. Moffat, D. Ballereau, J. Chauville, J. Zorec and C. A. Poteet A&A, 530 (2011) A151 Published online: 27 May 2011 DOI: 10.1051/0004-6361/201116567