1. Is There One Best Orthodontic Appliance?;Steiner;Dental Cosmos,1933
2. Force Control in the Movement of Dental Structures—A Technique Designed to Apply Its Principles;Carey;Angle Orthodontist,1951
3. Timoshenko, S., and McCullough, G. H.: Elements of Strength of Materials, ed. 2, Part I, New York, Duan O. Strand Co., pp. 148, 343.
4. Tinius Olsen Tour-Marshal Testing Company, Bulletin No. 5.