1. The mechanics of centric and eccentric cervical traction;Haak;Am. J. Orthod.,1958
2. Unilateral cervical traction with a Kloehn extraoral mechanism;Drenker;Angle Orthod.,1959
3. A mechanical appraisal of the Kloehn extraoral assembly;Oosthuizen;Angle Orthod.,1973
4. A key to the understanding of extraoral forces;Jacobson;Am. J. Orthod.,1979