Effects of formaldehyde on the frog's mucociliary epithelium as a surrogate to evaluate air pollution effects on the respiratory epithelium - Neyret, C. Fló; Lorenzi Filho, Geraldo; Macchione, Mariangela; Garcia, M. L. B.; Saldiva, Paulo Hilário Nascimento (Brazilian Journal of Medical and Biological Research, 2001)