1. Websters New International Dictionary,1934
2. Textbook of Orthodontics;G Singh,2007
3. Oral habits, prevalence and effects on occlusion of 4–15 year old school children in Lagos, Nigeria;R Quashie-Williams;Niger Postgrad Med J,2010
4. Oral habits in relation to dental caries and gingival health among children attending the dental hospital;MM Misbah;J Bagh Coll Dentistry,2005
5. Attitudes of Saudi Arabian mothers towards the digit-sucking habit in children;A Al-Jobair;Int J Paediatr Dent,2004