Pharmacodynamic comparison of levofloxacin, ciprofloxacin and ampicillin against Streptococcus pneumoniae in an in vitro model of infection - Lacy,M.K.; Lu,W.; Xu,X.; Nicolau,D.P.; Quintiliani,R.; Nightingale,C.H. (Antimicrob Agents Chemother, 1999)