1. Development of Gums and Their Relationship to the Deciduous Teeth in the Human Fetus;West,1920
2. Classification of the Upper Lip in Mammals;Boyd;J. Anat.,1933
3. Developmental Anatomy;Arey,1946
4. Human Embryology;Patten,1946
5. The Superior Labial Frenum and the Midline Diastema and Their Relation to Growth and Development of the Oral Structures;Ceremello;Am. J. Orthodontics,1953