1. The Gran Sasso Project;Zichichi,1981
2. The Gran Sasso Laboratory;Zichichi,1983
3. The Gran Sasso Project;Zichichi;INFN/AE-82/1,1982
4. Muon flux measurement in the Gran Sasso Laboratory;Cardarelli;INFN/AE-86/11,1986
5. E. Bellotti et al., INFN/TC-89-19 and references therein reported.