1. Eruption of Teeth as Physiological Standard for Testing Development;Bean;Pedagog. Sem,1914
2. Physiological Age and School Entrance;Beik;Pedagog. Sem,1913
3. Dentition as Measure of Maturity;Cattell,1928
4. Atlas of Skeletal Maturation;Todd,1937
5. Determination of Anatomical Age in School Children and Its Relation to Mental Development;Prescott;Harvard Monographs in Education,1923