References
Stafne E. C. Supernumerary teeth. Dental Cosmos.  1932;74:653–659.
Rubenstein L. K., Lindauer S. J., Issacson R. J., Germane N. Development of supernumerary premolars in an orthodontic population. Oral Surgery, Oral Medicine, Oral Pathology.  1991;71:392–395. doi: 10.1016/0030-4220(91)90324-6