1. Axell T, Henricsson V: Association between recurrent aphthous ulcers and tobacco habits. Scand J Dent Res 93:239–242,1985
2. Chellemi SJ, Olson DL, Shapiro S: The association between smoking and aphthous ulcers. Oral Surg Oral Med Oral Pathol 29:832–836,1970
3. Cooke BED: Recurrent oral ulcers. Br J Dermatol 81:159–161, 1969
4. Crivelli MR, Adler SAI, Quarracino C, et al.: Influence of socioeconomic Status on oral mueosa lesion prevalence in school children. Comm Dent Oral Epidemiol 16:58, 1988
5. DuBois A, van den Berghe L: Diseases of the warm climates: Their clinical features, diagnosis, and treatment. New York, Grüne & Stratton, 1948, p 380