1. Levels of evidence and journal impact factor in oral and maxillofacial surgery 
S.L. Lau, N. Samman 
International Journal of Oral and Maxillofacial Surgery 
Volume 36, Issue 1, Pages 1-5 (January 2007)
DOI: /j.ijom
Copyright © 2006 International Association of Oral and Maxillofacial Surgeons Terms and Conditions

2. Fig. 1
Overall distribution of levels of evidence in OMS articles published 2002–2003.
International Journal of Oral and Maxillofacial Surgery  , 1-5DOI: ( /j.ijom )
Copyright © 2006 International Association of Oral and Maxillofacial Surgeons Terms and Conditions

3. Fig. 2 Distribution of levels of evidence for each journal.
International Journal of Oral and Maxillofacial Surgery  , 1-5DOI: ( /j.ijom )
Copyright © 2006 International Association of Oral and Maxillofacial Surgeons Terms and Conditions

4. Fig. 3 Distribution of non-evidence articles.
International Journal of Oral and Maxillofacial Surgery  , 1-5DOI: ( /j.ijom )
Copyright © 2006 International Association of Oral and Maxillofacial Surgeons Terms and Conditions