Search for unstable heavy and excited leptons in e+e− collisions at ∝s = 170-172 GeV OPAL Collaboration, K. Ackerstaff, G. Alexander, J. Allison, N. Altekamp, K. vJ. Anderson, S. Anderson, S. Arcellie, S. Asai, D. Axen et al. (329 more) Eur. Phys. J. C, 1 1-2 (1998) 45-64 Published online: 27 February 2005 DOI: 10.1007/BF01245797