Resolution: standard / high

Figure 4.

Frequency of studies related to cough and environmental factors as assessed by a PubMed search for the terms "cough" and "environmental" and different publication dates.

Groneberg-Kloft et al. Journal of Occupational Medicine and Toxicology 2006 1:6   doi:10.1186/1745-6673-1-6
Download authors' original image