A study of the Civic Tower in Ravenna as an example of medieval towers' preservation problems Stefania Bruni, Giuseppe Maino, Elena Marrocchino, Carmela Vaccaro and Lisa Volpe Eur. Phys. J. Plus, 128 3 (2013) 33 Published online: 14 March 2013 DOI: 10.1140/epjp/i2013-13033-1