1. Design study for a 22 to 130 GeV e+e- colliding beam machine (LEP), pink book, CERN/ISR-LEP/79-33 (1979).
2. PEP, Conceptual design report, LBL-4288 and SLAC-189 (1976).
3. JADE Collaboration, S. Orito, Proc. Int. Symp. on Lepton and Photon Interactions - Fermilab (1979).
4. TASSO Collaboration, R. Brandelik et al., Phys. Lett. 83B (1979) 261.
5. T.P.C. Collaboration, A.R. Clark et al., PEP 4 (1976).