1. The level anchorage system;Root,1985
2. Clinical orthodontics;Tweed,1966
3. The application of the principles of the egdewise arch in the treatment of Class II, division 1, malocclusion;Tweed;part II. Angle Orthod,1936
4. Controlling the magnitude, direction and duration of extraoral force;Armstrong;Am J Orthod,1971
5. Risks and complications of orthodontic miniscrews;Kravitz;Am J Orthod Dentofacial Orthop,2007