Shim CS, Williams MH. Relationship of wheezing to the severity of obstruction in asthma. Arch Intern Med. May 1983, 143 (5): 890–2. PMID 6679232. doi:10.1001/archinte.143.5.890.
Pasterkamp H, Tal A, Leahy F, Fenton R, Chernick V. The effect of anticholinergic treatment on postexertional wheezing in asthma studied by phonopneumography and spirometry. Am Rev Respir Dis. Jul 1985, 132 (1): 16–21. PMID 3160273.
Shim CS, Williams MH. Relationship of wheezing to the severity of obstruction in asthma. Arch Intern Med. May 1983, 143 (5): 890–2. PMID 6679232. doi:10.1001/archinte.143.5.890.