References
- Fischer D. S., Singer D. H., Feldman S. M. Clubbing, a review, with emphasis on hereditary acropachy. Medicine 1964; 43: 459
- Sly M. R., Fuqua G., Matta E. G., Waring W. Objective assessment of minimal digital clubbing in asthmatic children. Annals of Allergy 1972; 30: 575–578