1. Die Krafte der orthodontischen gummuligatur;Bertran;Fortschr. Orthod.,1931
2. Measuring orthodontic forces;Paulich;Am. J. Orthod.,1939
3. A study of applied force as related to use of elastics and coil springs;Bell;Angle Orthod.,1951
4. Biophysical properties of orthodontic rubber;Newman;J. N. J. State Dent. Soc.,1963
5. The effect of environment on loss of tension in orthodontic elastics, rubber and plastic;Oliver,1968