1. An Investigation of Four Gypsum Materials Used To Prepare Indirect Inlay Models;Paffenbarger;J.A.D.A. and Dental Cosmos,1938
2. Hardness and Flow Properties of Gypsum Materials;Mahler;J. Pros. Den.,1951
3. The Hardness of Dental Plaster and Stone;Peyton;Univ. of Mich. Dental School Alumni Bulletin,1950
4. Reversible Hydrocolloid Impression Material: Its Treatment and Use in Operative and Prosthetic Dentistry;Thompson;J.A.D.A.,1949