Vacuum ultraviolet emission of a permanent magnet undulator on the ACO storage ring in Orsay J.M. Ortega, M. Billardon, G. Jezequel, P. Thiry et Y. Petroff J. Phys. France, 45 12 (1984) 1883-1888 DOI: 10.1051/jphys:0198400450120188300